Summer Training Report

2011

Summer Training Report

TRACTORS

ACKNOWLEDGEMENT

I have done my industrial training at HMT limited, Pinjore (Tractor division). During this period of my training I went to training centre. This has greatly enhanced my knowledge about the vast field of engineering.

I am extremely thankful to the management of HMT, Pinjore for giving me an opportunity to pursue training in their plant.

I am also thankful to Mr V.K. Grover (DGM, Training centre, HMT limited, Pinjore). I am thankful to all the workers and staff members to provide their cooperation and guidance to me.

I am deeply indebted to the training and placement departments in my institute and all other faculty members of institute for their valuable contribution towards my training.

I wish to express my deep gratitude to all the concerned persons with whose cooperation & coordination, I have successfully completed the training in the organization.

HMTs India

HMT FACTORIES IN INDIA

I and II BANGALORE MACHINE TOOLS DIES CASTING AND PLASTIC MOULDING MACHINES

III PINJORE TRACTORS AND MACHINE TOOLIV KALAMSERRY MACHINE TOOLS AND PRINTING

MACHINEV HYDERABAD MACHINE TOOLS AND LAMPSVI AJMER MACHINE TOOLSVII AURANGABAD FOOD PROCESSING MACHINERVIII HYDERABAD HMT BEARINGS LIMITED

WATCH FACTORIES

I and II BANGALORE KARNATKAIII SRINAGAR J & KIV TUMKUR KARNATKAV RANIBAGH UTTAR-PRADESH

MINIATURE BATTERY

GUWAHATI

ASSAM

TRACTOR ASSEMBLING LINES

PUNJAB HYDERABAD ANDHRA-PRADESH

INTRODUCTION TO H.M.T.

Hindustan Machine Tools  was incorporated in 1953 by the  Government of India  as a machine tool manufacturing company. Over the year’s diversified into watches, tractors,  printing machinery,  metal forming  presses,  die casting &  plastic  processing machinery, CNC systems & bearings. HMT is headquartered at Bangalore. Successful technology absorption in all product groups through collaborations with world renowned manufacturers and further strengthened by

continuous in-house R&D.

Today, HMT comprises six subsidiaries under the ambit of a holding company, which also

Type Public Sector Undertaking

Founded 1953

Headquarters Bangalore, India

Key people A.V. Kamet (Chairman and Managing Director)

Industry Engineering

Products Machine Tools, Tractors, Watches

Website www.hmtindia.com

Hindustan Machine Tools Ltd.

manages the tractors business directly.

HMT Limited has 18 manufacturing units. The constituent

subsidiaries are given below while the holding company retains the

tractors business group.

H.M.T.LIMITEDHMT Limited was established in 1953 in technical collaboration with M/s oerlikon of Switzerland. Over the years, many new products have been added to its manufacturing range. It has had technical collaboration with over 30 leading international Engineering Companies for manufactures of various products. HMT’s diversified product range include in Machine Tools, Watches, Tractors, Printing machines, Presses, Die casting and Plastic Injection Moulding machines, Foods processing machinery, CNC systems, Ball screws etc.

Today, HMT is a multi-product, multi-technology engineering complex with strengths comprising of:

16 Manufacturing units (22 Product Division)

Assets worth over US $ 250 million

Annual turnover of US $ 300 million

ISO 9000 accreditation

The widest range of machine tools, ranging from General purpose lathes to CNC turning / machining centres.

Source of qualified and experienced manpower.

HMT's Milestones

YEAR UNITS / DIVISION LOCATION STATE

1953 Machine Tools I Bangalore Karnataka

1961 Machine Tools II Bangalore Karnataka

1962 Watch Factory I Bangalore Karnataka

1963 Machine Tools III Pinjore Haryana

1965 Machine Tools IV Kalamassery Kerala

1967 Machine Tools V Hyderabad Andhra Pradesh

1971 Tractor Division Pinjore Haryana

1971 Die Casting Division Bangalore Karnataka

1972 Printing Machinery Division Kalamassery Kerala

1972 Watch Factory II Bangalore Karnataka

1973 Precision Machinery Division Bangalore Karnataka

1975 Machine Tools VI Ajmer Rajasthan

1975 HMT (International) Ltd. Bangalore Karnataka

1975 Watch Factory III Srinagar Jammu & Kashmir

1978 Watch Factory IV Tumkur Karnataka

1981 HMT Bearings Limited Hyderabad Andhra Pradesh

1981 Quartz Analog Watches Bangalore Karnataka

1982 Watch Factory V Ranibagh Uttar Pradesh

1982 Specialised Watch Case Division Bangalore Karnataka

1983 Stepper Motor Division Tumkur Karnataka

1985 Ball Screw Division Bangalore Karnataka

1986 CNC Systems Division Bangalore Karnataka

1991 Central Re-conditioning Division Bangalore Karnataka

H.M.T. (International) Limited

HMT(INTERNATIONAL) Limited, was set up in 1974 as a wholly owned subsidiary of hmt Limited, to undertake exports of goods manufactured by HMT and other leading Indian manufacturers.

HMT(I) is headquartered at Bangalore and has a global network extending over 38 countries with 67 representations to service its clientele worldwide. HMT(I) has sold over 12,500 machines in more than 70 countries with efficient after sales service.

HMT(I) also offers a comprehensive package of consultancy of technical and engineering services from concept to commissioning on turnkey basis. Its track record include prestigious projects in Algeria, Indonesia, Kenya, Malaysia, Mauritius, Tanzania, UAE, Maldives and other countries.

HMT(I)'s business portfolio includes trading in:

Machine Tool and Industrial Machinery

Watches Tractors & Agricultural Implements General Engineering Products Industrial Commodities Software and IT Services

HMT Fast Forward

It was in the early post-independence era that, HMT began in a small way to meet a big commitment;

'To manufacture mother machines to build modern industrial India'.

HMT was conceived by the Government of India in 1949, and was incorporated in 1953, with the objective of producing a limited range of machine tools, required for building an industrial edifice for the country.

THE 1960's:

With the success achieved in the initial years in absorbing the technology and in attaining production competence far ahead of the original plans, the Company launched a bold plan of diversification and expansion which resulted in the duplication of the Bangalore Unit and the setting up of new units at Pinjore, Kalamassery and Hyderabad.

In 1967, recession struck the Indian Engineering Industry and the consumption of machine tools dipped drastically. The traumatic years of recession did indeed serve to bring to the fore two latent strengths of HMT, namely, the urge to survive and the confidence to innovate. With these strengths at full play, the Company emerged from the recession:

With the world's widest range of machine tools and associated services under a single corporate entity.

With action plans firmly launched for diversification into Tractors, Presses and Press Brakes, Printing Machines, Die Casting and Plastic Injection Moulding Machines, Horological Machinery, etc., which were considered to have economic cycles that are different from those of machine tools.

With a Watch Factory already established in 1961-62, additional capacities for watch production were contemplated to provide a greater cushion against cyclical fluctuations in capital goods markets and also to meet the burgeoning demand for watches.

With export markets of enormous potential under active development.

THE 1970's:

The 70s witnessed the fructification of all the diversification plans as envisaged.

HMT setup

HMT International Limited as a subsidiary company to channel HMT's products and technical services abroad.

Two more units for manufacture of Watches, one at Srinagar and one at Tumkur

HMT took over Machine Tool Corporation at Ajmer as its sixth machine tool unit.

THE 1980's:

In the 80s, HMT as a part of vertical integration efforts, launched units to manufacture

Watches at Ranibagh Watch Cases at Bangalore Stepper Motors at Tumkur CNC Systems at Bangalore Ball screws for use on CNC machines at Bangalore etc.,.

Also

HMT took over Indo-Nippon Precision Bearings Ltd, a state owned unit as a subsidiary, which was renamed HMT-Bearings Ltd.

HMT took over Praga Tools Ltd as another subsidiary.

THE 1990's:

The Company restructured itself into five Business Groups viz., Machine Tools, Watches, Tractors, Industrial Machinery and Engineering Components as part of Business Reorganisation.

The New Millennium

HMT is now restructured with addition of three more subsidiaries to those already existing. HMT now comprises of six subsidiaries under the ambit of the Holding Company which also manages the Tractors business directly.

HMT Machine Tools Limited, Bangalore HMT Watches Limited, Bangalore HMT Chinar Watches Limited, Jammu HMT Bearings Limited, Hyderabad Praga Tools Limited, Hyderabad HMT (International) Limited, Bangalore

The strategic plans of the HMT group is coordinated by the holding company at Bangalore.

To navigate through the challenges of the new millennium, HMT seeks strategic alliances from global leaders to synergise its own strengths with symbiotic inputs from the partners.

For us, the whole world of opportunities is ahead to emerge as a global engineering conglomerate.

HMT TRACTORS LIMITED

HMT TRACTORS – THE POWER Behind Farm Mechanisation

Pioneers of Farm Mechanization in India

HMT rolled out its first 25 HP tractor in collaboration with Motokov of erstwhile Czekoslovakia from its Pinjore plant in the state of Haryana. The successful of the 25 HP tractor in India conditions led HMT to indigenise the 25 HP in a short span of five years.

And that was just the beginning………

The passing years, saw the needs of the Indian farmer change. Farm mechanization was growing at a rapid pace and called for more powerful and multi-role tractors.

HMT stepped in by introducing tractors that met the specific needs of the agricultural sector. HMT manufactures a wide range from 25 HP to 75 HP. Keeping in tune with HMT’s philosophy of introducing innovative products and continuously upgrading its tractors with better technology, these products and continuously upgrading its tractors with better technology, these products and continuously upgrading its tractors with better technology, these models incorporate contemporary technology viz. fuel efficient engine meeting emission norms, floor gears, direct axle, latest styling giving value for money to its customers.

HMT – A PROFILE

Incorporated in 1953 by the Government of India as a Machine Tool manufacturing company.

Over the years diversified into Watches, Tractors, Printing Machinery, Metal Forming Presses, Die Casting & Plastic Processing Machinery, CNC Systems & Bearings.

Successful technology absorption in all product groups through collaborations with world renowned manu- facturers & further strengthened by continuous inhouse R&D.

Today, HMT comprises five subsidiaries under the ambit of a Holding Company, which also manages the Tractors Business directly.

Our Vision and Mission

Our Corporate VisionOur Corporate Mission

 To establish ourselves as one of the world’s premier companies in the engineering field having strong international competitiveness

 To achieve market leadership in India through ensuring customer satisfaction by supplying internationally competitive products and services

 To achieve sustained growth in the earnings of the group on behalf of shareholders

Our Corporate Objectives & Goals

To encourage the modernisation of Indian Industry through the supply of engineering goods and services of world class excellence

To maintain technological leadership through continuous efforts to update product technology and manufacturing methods

To globalise our operations by developing a mix of international markets and businesses

To ensure a satisfactory return on capital employed, to meet the growth needs and the aspirations of our stakeholders

To present an active, pleasant and productive working environment

Our Corporate Strengths

Our Business Domain

HMT Limited - Holding Company

HMT Limited, with a diverse range of products, over 18 manufacturing units and a countrywide well established marketing network restructured its various businesses into different subsidiaries under the ambit of a holding company. The constituent subsidiaries of HMT Limited are as below while the holding company retains the Tractors Business Group.

HMT's Products

Sl.No.

Name of Subsidiary% Holding

1 HMT Machine Tools Limited 100

2 HMT Watches Limited 100

3 HMT Chinar Watches Limited 100

4 HMT International Limited 100

5 HMT Bearings Limited 97.25

6 Praga Tools Limited 51.00

The Holding Company with its Corporate Head Quarters at Bangalore forms the hub for the activities of the different subsidiaries. The Holding Company while ensuring good corporate governance also pursues strategies such as

Creation of strategic alliances, Development of brand equity, Provision of strategic planning inputs, Interface with regulatory agencies, Creation and maintenance of data warehouse with suitable

corporate informational data for the use of all subsidiaries.

HMT’s TRACTORS BUSINESS

HMT’s Tractor business commenced its operations in 1971 in technical collaboration with M/s MOTOKOV, Czechoslovakia Republic. Initially, HMT started the operation with the manufacture of 25 HP Tractor at the manufacturing plant established in Pinjore, Haryana State.

Over the years, it has developed Tractors ranging from 25 HP to 75 HP. The company achieved market leadership in tractors by enlarging its range to cover most of the applications for the farming community.

Currently the company has three tractor manufacturing units in India located at Pinjore in Haryana, Mohali in Punjab and Hyderabad in Andhra Pradesh. It has a well equipped R&D Center duly recognized by the Department of Scientific and Industrial Research , the Government of India.

The Tractor Business Group of HMT has been a proud recipient of a number of National Level - Productivity Awards. It has also been certified for ISO-9001 by KEMA, Netherlands.

It has an installed capacity of 18,000 Tractors for manufacturing and assembly operations. It has an in-house marketing organization comprising 17 Area Offices, 11 Stockyards and over 300 Dealers spread across the country. HMT Tractors Group is ably supported by over 40 Ancillary Units. It has qualified and experienced workforce.

HMT has produced and marketed over 3,60,000 Tractors since inception in India and abroad.

VISION,MISSION,COMMITMENT OF TRACTOR DIVISION

VISION:

TO BE THE PRE-EMINENT CATALYST IN COUNTRY’S FARM MECHANIZATION EFFORTS BY PROVIDING PRODUCTS THAT IS FARMERS’ DELIGHT.

MISSION:

To establish ourselves as one of the world’s premier companies in the engineering field having strong international competitiveness

To achieve market leadership in India through ensuring customer satisfaction by supplying internationally competitive products and services

To achieve sustained growth in the earnings of the group on behalf of shareholders

COMMITMENT:

We shall

Strive continuously to assure you of highest standard of service Strive to attain international standards to become globally

competitive. Acknowledge all correspondence from you within a reasonable

time of its receipt with absolute integrity and dedication Adhere to the delivery schedules committed by us to you Strictly adhere to the standards, specifications stipulated in ISO-

9001-2000 Always maintain the highest ethical standards in all our

endeavours, business and economic activities

CONTENTS

o TRAINING CRENTER

o FOUNDRY

o HEAVY MACHINE SHOP

o ENGINE SHOP

o ENGINE ASSY. AND TESTING

o NEW ENGINE SHOP

o TRACTOR ASSYMBLY

o LIGHT MACHINE SHOP

o TOOL ROOM

o HEAT TREATMENT

TURNING:

Turning is the process whereby a single point cutting tool is parallel to the surface. When turning, a piece of material (wood, metal, plastic, or stone) is rotated and a cutting tool is traversed along 2 axes of motion to produce precise diameters and depths. Turning can be either on the outside of the cylinder or on the inside (also known as boring) to produce tubular components to various geometries.

The turning processes are typically carried out on a lathe, considered to be the oldest machine tools, and can be of four different types such as straight turning, taper turning, profiling or external grooving. Those types of turning processes can produce various shapes of materials such as straight, conical, curved, or grooved workpiece.

Turning operations:

Turning specific operations include:

Turning

This operation is one of the most basic machining processes. That is, the part is rotated while a single point cutting tool is moved parallel to the axis of rotation.[1] Turning can be done on the external surface of the part as well as internally (boring). The starting material is generally a workpiece generated by other processes such as casting, forging, extrusion, or drawing.

Tapered turning

a) from the compound slide b) from taper turning attachment c) using a hydraulic copy attachment d) using a C.N.C. lathe e) using a form tool e) by the offsetting of the tailstock - this method more suited for shallow tapers.

Hard turning 

Hard turning is a turning done on materials with a Rockwell C hardness greater than 45. It is typically performed after the workpiece is heat treated.

The process is intended to replace or limit traditional grinding operations. Hard turning, when applied for purely stock removal purposes, competes favourably with rough grinding. However, when it is applied for finishing where form and dimension are critical, grinding is superior. Grinding produces higher dimensional accuracy of roundness and cylindricity.

Facing 

is part of the turning process. It involves moving the cutting tool at right angles to the axis of rotation of the rotating workpiece. This can be performed by the operation of the cross-slide, if one is fitted, as distinct from the longitudinal feed (turning). It is frequently the first operation performed in the production of the workpiece, and often the last- hence the phrase "ending up".

Parting

This process is used to create deep grooves which will remove a completed or part-complete component from its parent stock.

Grooving

is like parting, except that grooves are cut to a specific depth by a form tool instead of severing a completed/part-complete component from the stock. Grooving can be performed on internal and external surfaces, as well as on the face of the part (face

grooving or trepanning).

Non-specific operations include:

Boring

i.e. the machining of internal cylindrical forms (generating) a) by mounting workpiece to the spindle via a chuck or faceplate b) by mounting workpiece onto the cross slide and placing cutting tool into the chuck.

Drilling 

is used to remove material from the inside of a workpiece. This process utilizes standard drill bits held stationary in the tail stock or tool turret of the lathe.

Knurling 

The cutting of a serrated pattern onto the surface of a part to use as a hand grip using a special purpose knurling tool

Reaming

Threading 

both standard and non-standard screw threads can be turned on a lathe using an appropriate cutting tool. (Usually having a 60, or 55° nose angle) Either externally, or within a bore. Generally referred to as single-point threading.

tapping of threaded nuts and holes a) using hand taps and tailstock centre b)using a tapping device with a slipping clutch to reduce risk of breakage of the tap

threading operations include a)all types of external and internal thread forms using a single point tool also taper threads, double start threads, multi start threads, worms as used in worm wheel reduction boxes, leadscrew with single or multistart threads. b) by the use of threading boxes fitted with 4 form tools, up to 2" diameter threads but it is possible to find larger boxes than this. Lathes

LATHE

A lathe is a machine tool used principally for shaping pieces of metal, wood, or other materials by causing the workpiece to be held and rotated by the lathe while a tool bit is advanced into the work causing the cutting action. Lathes can be divided into three types for easy identification: engine lathe, turret lathe, and special purpose lathes. Some smaller ones are bench mounted and semi-portable. The larger lathes are floor mounted and may require special transportation if they must be moved. Field and maintenance shops generally use a lathe that can be adapted to many operations and that is not too large to be moved from one work site to another. The engine lathe is ideally suited for this purpose. A trained operator can accomplish more machining jobs with the engine lathe than with any other machine tool. Turret lathes and special purpose lathes are usually used in production or job shops for mass production or specialized parts, while basic engine lathes are usually used for any type of lathe work.

Types of Lathes:

o Centre Lathe

o Production Lathe

Capstan Lathe

Turret Lathe

o Special Lathe

Parts

of Lathe

Machine:

TRACTOR

A tractor is a vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially (and originally) tillage but nowadays a great variety of tasks.

PARTS OF TRACTOR:

o Engine o Gear Box

o MT Housing o Wheel

o Steering o Brakes

o Radiator o Fan

o Oil Tank o Oil Pump

o Hydraulic Lift o P.T.O

o Oil Filter o Battery

o Altinater o Starter

o Exhaust Pipe o Measuring Meter

Tractor Model HP Main Feature

2522 25 AVL fuel efficient engine & New Style Bonnet

3022 30 Fuel efficient engine (HMT’s Design) New

Style Bonne

3522 35 AVL adapted fuel efficient engine & New

Style Bonnet

4511 45 HMT Design

5911 58 Heavy Duty Tractor (Czech’s Design)

7511 75 HMT’s Design, Power Steering & ROPS

2522 OS 25 Low height and width for orchard

applications

3522 CS 35 Wetland cultivation

3522 DX 35 Direct Axle Drive

4511 CS 45 Wetland cultivation

4922 EDI 49 AVL adapted fuel efficient engine & New

Style Bonnet OS = Orchard Special ; CS = Coastal Special ; DX = Direct Axle

Facility of HMT Tractor:

Power Steering

Hydraulic Lift & Hydraulic Brakes

Reverse P.T.O. System

Trem III System use to control the environment Pollution

Less Wear Tear

Less Cost needs for working

MILLING

Milling is the most common form of machining, a material removal process, which can create a variety of features on a part by cutting away the unwanted material. The milling process requires a milling machine, workpiece, fixture, and cutter. The workpiece is a piece of pre-shaped material that is secured to the fixture, which itself is attached to a platform inside the milling machine. The cutter is a cutting tool with sharp teeth that is also secured in the milling machine and rotates at high speeds. By feeding the workpiece into the rotating cutter, material is cut away from this workpiece in the form of small chips to create the desired shape.

Classification:

Face Milling

Peripheral Milling

Saddle Milling

Milling Machine Classified as:

Vertical Milling Machine

Horizontal Milling Machine

There are alternate classification according to method of control, size, purpose, & power source.

Vertical mill

In the vertical mill the spindle axis is vertically oriented. Milling cutters are held in the spindle and rotate on its axis. The spindle can generally be extended (or the table can be raised/lowered, giving the same effect), allowing plunge cuts and drilling. There are two subcategories of vertical mills: the bed mill and the turret mill.

A turret mill has a stationary spindle and the table is moved both perpendicular and parallel to the spindle axis to accomplish cutting. The most common example of this type is the Bridgeport, described below. Turret mills often have a quill which allows the milling cutter to be raised and lowered in a manner similar to a drill press. This type of machine provides two methods of cutting in the vertical (Z) direction: by raising or lowering the quill, and by moving the knee.

In the bed mill, however, the table moves only perpendicular to the spindle's axis, while the spindle itself moves parallel to its own axis.

Turret mills are generally considered by some to be more versatile of the two designs. However, turret mills are only practical as long as the machine remains relatively small. As machine size increases, moving the knee up and down require considerable effort and it also becomes difficult to reach the quill feed handle (if equipped). Therefore, larger milling machines are usually of the bed type.

Horizontal mill

A horizontal mill has the same sort of x–y table, but the cutters are mounted on a horizontal arbor (see Arbor milling) across the table. Many horizontal mills also feature a built-in rotary table that allows milling at various angles; this feature is called a universal table. While endmills and the other types of tools available to a vertical mill may be used in a horizontal mill, their real advantage lies in arbor-mounted cutters, called side and

Vertical milling machine. 1: milling cutter 2: spindle 3: top slide or overarm 4: column 5: table 6: Y-axis slide 7: knee 8: base

Horizontal milling machine. 1: base 2: column 3: knee 4 & 5: table (x-axis slide is integral) 6: overarm 7: arbor (attached to spindle)

face mills, which have a cross section rather like a circular saw, but are generally wider and smaller in diameter. Because the cutters have good support from the arbor and have a larger cross-sectional area than an end mill, quite heavy cuts can be taken enabling rapid material removal rates. These are used to mill grooves and slots.

Grinding:

It is an abrasive machinery process that uses grinding wheels as the cutting tool.

Its purpose is to produce very fine finish

and very precise dimensions.

Types:

Surface Grinding

Cylindrical Grinding

Internal Grinding

Centre less Grinding

Ultra High Speed Grinding

FOUNDRY

A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal in a mould, and removing the mould material or casting after the metal has

solidified as it cools. The most common metals processed are aluminium and cast iron. However, other metals, such as bronze, steel, magnesium, copper, tin, and zinc, are also used to produce castings in foundries.

We perform these processes under foundry:

MELTING

FURNACE

DEGASSING

MOULD MAKING

POURING

SHAKE-OUT

DEGATING

SURFACE CLEANING

HEAVY MACHINE SHOP:

All the heavy parts of tractor are

machined.

Gear box housing

Main transmission housing

Hydraulic lift

ENGINE SHOP:

TRACTOR ASSEMBLY

HEAT TREATMENT(T) :

Heat treatment is metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other

materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering and quenching. It is noteworthy that while the term heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding.

COMMONLY USED TERMS & OPERATIONS:

CARBURIZING

Carburizing is a heat treatment process in which iron or steel is heated in the presence of another material (in the range of 900 to 950 °C (1,650 to 1,740 °F)) which liberates carbon as it decomposes. Depending on the amount of time and temperature, the affected area can vary in carbon content. Longer carburizing times and higher temperatures lead to greater carbon diffusion into the part as well as increased depth of carbon diffusion. When the iron or steel is cooled rapidly by quenching, the higher carbon content on the outer surface becomes hard via the transformation from austenite to martensite, while the core remains soft and tough as a ferritic and/or pearlite microstructure.[1]

This manufacturing process can be characterized by the following key points: It is applied to low-carbon workpieces; workpieces are in contact with a high-carbon gas, liquid or solid; it produces a hard workpiece surface; workpiece cores largely retain their toughness and ductility; and it produces case hardness depths of up to 0.25 inches (6.4 mm).

Change in material properties

Work material properties Effects of carburizingMechanical Increased surface hardness

Increased wear resistance Increased fatigue/tensile strengths

Physical Grain Growth may occur Change in volume may occur

Chemical Increased surface carbon content

TEMPERING

Tempering is a heat treatment technique for metals, alloys and glass. In steels, tempering is done to "toughen" the metal by transforming brittle martensite or bainite into a combination of ferrite and cementite or sometimes Tempered martensite. Precipitation hardening alloys, like many grades of aluminum and superalloys, are tempered to precipitate intermetallic particles which strengthen the metal. Tempering is accomplished by a controlled reheating of the work piece to a temperature below its lower critical temperature.

The brittle martensite becomes tough and ductile after it is tempered. Carbon atoms were trapped in the austenite when it was rapidly cooled, typically by oil or water quenching, forming the martensite. The martensite becomes strong after being

tempered because when reheated, the microstructure can rearrange and the carbon atoms can diffuse out of the distorted body-centred-tetragonal (BCT) structure. After the carbon diffuses, the result is nearly pure ferrite with body-centred structure.

In metallurgy, there is always a trade-off between strength and ductility. This delicate balance highlights many of the subtleties inherent to the tempering process. Precise control of time and temperature during the tempering process are critical to achieve a metal with well balanced mechanical properties.

NORMALISING

Normalizing Is a heat treatment process (predominantly used on Steels)

It makes the material softer but does not produce the uniform material properties of annealing.

A material is normalized by heating it to a specific temperature and then letting the material cool to room temperature outside of the oven. This refines the grain size and improves the uniformity of microstructure and properties of hot rolled steel.

Normalizing is used in some in the production of large forgings such as: railroad wheels and axles and on some bar products.

The process is less expensive than annealing.

INDUCTION HARDENING

Induction hardening is a form of heat treatment in which a metal part is heated by induction heating and then quenched. The quenched metal undergoes a martensitic transformation, increasing the hardness and brittleness of the part. Induction hardening is used to selectively harden areas of a part or assembly without affecting the properties of the part as a whole.

A widely used process for the surface hardening of steel. The components are heated by means of an alternating magnetic field to a temperature within or above the

transformation range followed by immediate quenching. The core of the component remains unaffected by the treatment and its physical properties are those of the bar from which it was machined, whilst the hardness of the case can be within the range 37/58 HRC. Carbon and alloy steels with an equivalent carbon content in the range 0.40/0.45% are most suitable for this process.[1]

A source of high frequency electricity is used to drive a large alternating current through a coil. The passage of current through this coil generates a very intense and rapidly changing magnetic field in the space within the work coil. The workpiece to be heated is placed within this intense alternating magnetic field where eddy currents are generated within the workpiece and resistance leads to Joule heating of the metal.

This operation is most commonly used in steel alloys. Many mechanical parts, such as shafts, gears, and springs, are subjected to surface treatments, before the delivering, in order to improve wear behavior. The effectiveness of these treatments depends both on surface materials properties modification and on the introduction of residual stress. Among these treatments, induction hardening is one of the most widely employed to improve component durability. It determines in the work-piece a tough core with tensile residual stresses and a hard surface layer with compressive stress, which have proved to be very effective in extending the component fatigue life and wear resistance.[3]

Induction surface hardened low alloyed medium carbon steels are widely used for critical automotive and machine applications which require high wear resistance. Wear resistance behavior of induction hardened parts depends on hardening depth and the magnitude and distribution of residual compressive stress in the surface layer.

QUENCHING

In materials science, quenching is the rapid cooling of a workpiece to obtain certain material properties. It prevents low-temperature processes, such as phase transformations, from occurring by only providing a narrow window of time in which the reaction is both thermodynamically favorable and kinetically accessible. For instance, it can reduce crystallinity and thereby increase toughness of both alloys and plastics (produced through polymerization).

In metallurgy, it is most commonly used to harden steel by introducing martensite, in which case the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable. In steel alloyed with metals such as nickel and manganese, the eutectoid temperature becomes much lower, but the kinetic barriers to phase transformation remain the same. This allows quenching to start at a lower temperature, making the process much easier. High speed steel also has added tungsten, which serves to raise kinetic barriers and give the illusion that the material has been cooled more rapidly than it really has. Even cooling such alloys slowly in air has most of the desired effects of quenching.

Extremely rapid cooling can prevent the formation of all crystal structure, resulting in amorphous metal or "metallic glass".

SAND BLASTING

Sand blasting is a process where in abrasives such as grit, sand or shot are propelled with compressed air on to the substrate to remove millscale, oil, grease, dirt, rust, oxides & paint. Surface preparation is the most popular method for any protective coating adhere.As per the IS and BS standards, while doing this process, the place will be covered by tarpaulin because of dust particle should not spreaded other places.

HEAT TREATMENT PROCESS PARAMETER

o Carburising

Preheat at 300 to 400 degree Celsius

Carburise at 900-930 degree Celsius for 8-10 hrs

o Annealing

Salt bath (barium chloride) at 650-670 degree Celsius

Soaking time is 2-5 hrs

o Case hardening

Salt bath (Sodium cynide+ Barium chloride) at 760-830 degree Celsius & soaking for 10-12 min

Quenching at 160-180 degree Celsius (nirite+ nitrate) for 5-10 min

Tempring is done at 170-210 degree Celsius for one hour

It may be noted that carbon percentage to be maintained is .9-1.1%.

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