Welding 2

A Brief synopsis of:

Terms & Definitions

Duties & Responsibilities

Welding Imperfections

Mechanical Testing

Welding Procedures & Approval

Welder Approval

Any Questions ?*

1) Use a pencil only for the arrow line, but make all writing in ink

3) Do not forget to compare and sentence your report to the code provided

2) Report everything that you can observe

4) Do not forget to date & sign your report

5) Make any observations, such as recommendations for further investigation for crack-like imperfections*

Using the macro photographs and report sheets given to you, prepare your reports using the sheets given (20 min’s/macro)

Identify indications, then draw a line on the report sheet smaller macro photograph and number it. Using the boxes below, identify the number and indicate what you have identified

Place the size of the indication in the next box on the right, remembering to divide the dimension from photograph by 10

Use the following slides as guidance!

Macro Inspection Points1) Use a pencil for the arrow lines, but make all

writing in ink only

2) Do not forget to print your name

3) Do not forget to put the date

4) Do not forget to SIGN the report

5) Make any comments such as recommendations for further investigation for crack-like imperfections*

Macro Photo x 10*

09.20

Example Macro Photo

NOTE: PHOTOGRAPH IS AT X10 MAGNIFICATION

MATERIAL: LOW CARBON STEEL WELDING PROCESS: [MAG/GMAW]

1

Overlap + 2 pores# DEFECT SIZE ACCEPT/REJECT1      

2      

3      

4      

5      

6      

7    

8      

9      

10      

11 EXCESS WELD METAL    

12 EXCESS PENETRATION    

Laminations/inclusions*

2 3

Lack of side wall fusion*

4

Overlap*

5

Linear misalignment 0.4*

6

Lack of inter-run fusion + silica*

7

Gas pore/pipe ? Check penetrantLack of side wall fusion + silica*

8

Poor toe blend

9

11

4.7*1.4 Sharp*

All dimensions in mm

12

5°*Angular misalignment

10

Sharp 75° *

2.2 Ø *

Assess

To

Specification*

0.5 Ø max *

Continue with Practical Macro Inspection.

(Or as directed by your lecturer/presenter)*

10.45

Materials arriving at the site need to be inspected for the following:

1) Size

2) Condition

3) Specification*

Rolling Imperfections

LaminationsSegregation

Cold Laps*

Direction of rolling

Plate Inspection

Size

Condition (Corrosion, Mechanical damage, Laps, Bands and Laminations)

5L

Specification

Other checks may need to be made such as: distortion tolerance, number of plates and storage*

Pipe InspectionCondition (Corrosion, Damage, Wall thickness Ovality, Laminations & Seam)

Specification

Other checks such as: distortion, tolerance, number and storage*

Welded seam Size

LP 5

General discussion on areas of industry employing codes or standards*

Discuss the 3 areas of responsibility:

DesignManufactureTesting*

The 3 agencies generally identified in a code or standard:*

Codes & standards often do not contain all relevant data, but may refer to other standards*

1) The customer, or client*

2) The manufacturer, or contractor*

3) The 3rd party inspection, or clients representative*

Interpretation of Drawings & Weld Symbols

It could be strongly argued that without a thorough knowledge of weld symbols, a welding inspector is unable to fully carry out his full scope of work*

Welding SymbolsMost weld symbols contain 5 elements, which are:

1) The arrow line*

2) The reference line*

3) The symbol*

4) The dimensions*

5) The supplementary information*

a. 7 b. 10111*

5 x 100 (100)

1) Convention of the arrow line:

BS. BSEn & AWS  a)   Shall touch the joint intersection

b) Shall not be parallel to the drawing

c) Shall point towards a single plate preparation*

*

2) Convention of The reference line:

BS 499 (UK) & AWS A 2.4 (US)

a)        Shall touch the arrow line

b) Shall be parallel to the bottom of the drawing*

*

 Symbols: BS 499 (UK) & AWS A2.4 (US)a) Welds this side of joint, go underneath the reference line

b) Welds the other side of the joint, go on top of the reference line

c) Symbols with a vertical line component must be drawn with the vertical line to the left side of the symbol

d) All CSA dimensions are shown to the left of the symbol

e) All linear dimensions are shown on the right of the symbol i.e. Number of welds, length of welds, length of any (spaces)*

10 4 x 50 (50)*

Fillet weld

Double V

Double bevel

Double U

Double J*

Representation of welds done from both sides of the joint intersection, touched by the arrow head

Concave or Convex

Supplementary Weld SymbolsSupplementary Weld Symbols

Toes to be ground smoothly. (BSEn only))Site Weld

Weld all round

Ground flush

111

Welding process. Numerical BS En & BS

Further supplementary information, such as WPS number, or NDT may be placed in the fish tail*

3) Convention of The reference line:

BS En 22553 or ISO 2553a)    Shall touch the arrow line

b) Shall be parallel to the bottom of the drawing

c) There shall be a further broken line above or beneath the reference line (Except where the weld is

symmetrical)*or *

  Symbols: BSEn 22553. (ISO 2553)a) Welds this side of joint, go on the unbroken reference line

b) Welds the other side of the joint, go on the broken reference line

c) Symbols with a vertical line component must be drawn with the vertical line to the left side of the symbol

d) All CSA dimensions are shown to the left of the symbol

e) All linear dimensions are shown on the right of the symbol i.e. Number of welds, length of welds, length of any spaces

f) All leg lengths shall be preceded by z and throat by a or s*

z 10 4 x 50 (50)*

Weld Symbols on Drawings

88

5

a 5 b 8

8

BS 499 & AWS A 2.4

*

Weld Symbols on Drawings

8

z 8

5

a 5 z 8

8

BS En 22553 (ISO 2553)

or

or

z 8

a 5 z 8 *

Example:

Produce a drawing giving symbols for the welds given as shown below to the specification given

Weld Drawing BS 499

Symbol Drawing

MMA

111*

Example:

Student Symbols ExerciseComplete a symbols drawing for the welded joint given below to BS 499BS 499 && BSEn 22553BSEn 22553

10

All Fillet weld leg lengths are 10 mm *

20

30

35

15

7

All butt welds are MIG welded and all fillet welds with MMA

Solution BS 499 10a. 30

a. 20

10

a. 7 b 10

a. 35

a. 15

10

*

111 131

111 131

Solution BSEn 22553 z. 10

s. 30

s. 20

z. 10

a. 7 z. 10

s. 35

s. 15

z. 10

*

111 131

111 131

Special equipment used with method, for producing welds

Requirements:

To make a sound weld we need to

Protection

Properties

Heating

Cleaning

A welding process:*

Before continuing with the welding processes section, there are 2 safety related terms that should first be understood*

“Duty Cycle” relates to the current carrying capacity of all conductors, based on a 10 minute cycle i.e. 60% duty cycle means it can carry the specified current for 6 minutes in 10 then must rest for 4. A 100% duty cycle has no rest period requirement. (Explained fully in the WIS 5 course notes)*

Fume or gas Exposure Limit Effect on Health

Cadmium0.025Mg/m3Extremely toxic

General Welding Fume5Mg/m3Low toxicity

Iron5Mg/m3Low toxicity

Aluminium5Mg/m3Low toxicity

Ozone0.20 PPMExtremely toxic

Phosgene0.02 PPMExtremely toxic

Argon No OEL Value O2 air content to be

controlled

Very low toxicity

OEL/MEL (Occupational or Maximum Exposure Limit) which is used in reference to fume exposure such as that caused in arc welding. The value may be in PPM or mg/m3 depending on a particulate fume, or a gas. Typical values in EH/40 are*

Volts

Amps

OCV

Constant Current/Amperage Volt Amp Characteristic*

Large change in voltage =

Smaller change in amperage*

Welding Voltage*

Large arc gap*

Small arc gap

Electrode oven (Up to 350 °C)

Power return cable

Safety visor (With dark lens) *

Power source. Transformer/Rectifier

Holding Oven (Up to 200 °C)

Inverter power source

Electrode holder

Power cable

Power control panel

Electrodes

3) Electrode holder

1) A Transformer/Rectifier (Constant current type)

2) A power and power return cable

4) Electrode (To correct specification)

5) Correct visor & glass, all safety clothing and extraction

5) Electrode type & Ø

1) Amperage

3) Polarity

7) Electrode condition

9) Insulation / extraction

2) Arc Voltage

4) Speed of Travel

6) Duty Cycles

8) Connections

10) Electrode treatments*

3) Porosity

1) Slag inclusions

2) Arc strikes

4) Undercut

Most welding imperfections in MMA are caused by a lack of welder skill, the incorrect settings of the equipment, or the incorrect use, and treatment of electrodes*

Advantages:

1) Field or shop (Portable)

2) Range of consumables

3) All positional

4) *Quick electrode change

Disadvantages:

1) High skill factor

2) Short electrode length

5) Simple equipment

3) **Low productivity (OF)

4) High level of fume

5) Hydrogen control

* Enabling fast changes in material types to be welded** Comparatively uneconomic with other processes*

Inverter power source

Power cable

Flow-meter

Power control panel

Transformer/ Rectifier

Power control panel

Power return cable

Torch assemblies

Tungsten electrodes*

Ceramic shield cup

Gas lens

Torch body

Tungsten electrodes

Spare ceramic shielding cup *

Gas diffuser

Split collet

On/Off switch

Fitted ceramic shielding cup

Tungsten housing

The tungsten must have the correct vertex angle*

Grinding is done on a special jig, and on a dedicated wheel*

Correctly adjusted shielding with a gas lens will give good cover without turbulence*

Adjustments to the flow rate need to made according to joint design and gas type*

A fusible insert is pre-formed and placed filler material that is mainly used in the root of TIG welded pipes*

The Electric Boat Company of America, who developed it*

It is often termed an “EB insert” after*

Before welding

After welding*

1) A Transformer/Rectifier (Constant current type)

2) A power and power return cable

3) An Inert shielding gas. (Argon or Helium)

4) Gas hose, flow-meter, & gas regulator

5) TIG torch head with ground tungsten, collets, ceramics

6) Method of arc ignition (High frequency or lift arc)

7) Correct visor, all safety clothing and good extraction

8) Optional filler rod, to correct specification*

5) Tungsten type & Ø

1) Amperage

3) AC or DC + Polarity

7) Tungsten vertex angle

9) Gas type & flow rate

2) Arc Voltage

4) Speed of Travel

6) Duty Cycles

8) Connections

10) Insulation / extraction

11) Ceramic condition 12) Gas lens fitted*

2) Surface porosity (Loss of gas shield mainly on site)

1) Tungsten inclusions (Low skill, or wrong vertex angle)

3) Crater pipes (Bad weld finish technique i.e. Slope out)

Most welding imperfections with TIG are caused by a lack of welder skill, or incorrect setting of the equipment. i.e. Current, torch manipulation, welding speed, gas flow rate, etc*

4) Oxidation of S/S weld bead, or root by poor gas cover

Advantages:

1) High quality

2) High control of weld pool

3) All positional

4) Lowest H2 arc process

Disadvantages:

1) Very high skill factor

2) Range of consumable

5) Low inter-run cleaning

3) Loss of gas shield/site

4) Low productivity (O/F)

5) High ozone levels*

Videos

TWI

“Welding with covered electrodes”

ESAB

“TIG Welding Steels & Stainless Steels”

Or equivalent (1 hour)*

1) Use a pencil for the arrow lines, but make all written comments and measurements in ink only

3) Do not forget to compare and sentence your report

2) Report everything that you can observe

5) Do not forget to date & sign your report

6) Make any observations, such as recommendations for further investigation for crack-like imperfections i.e. penetrant testing*

WTC 7 Text Ref Section 17WIS 5 Text Ref Section 23Slides 52 - 60

The purpose of this session is to practice the reporting format required by CSWIP in the practical plate examination part of the CSWIP 3.1 Welding Inspectors exam

Remember, the responsibilities of a welding inspector are:

Observe

Report

Compare*.

To observe welding imperfections you are required to have good close vision acuity

A close vision acuity test will be given to you before your exam to establish if your vision meets the minimum standard required

Its not just the project that must meet the standard!!

You will also require a thorough knowledge of welding imperfections and their likely location, causes and implications*

After you have observed an imperfection and determined its type, you must be able to take measurements and complete a report *

The first report should be in the form of a repair map of the weld. (i.e. All observations are Identified Sized and Located)

Should the imperfection be a defect and require repair, it will need to be accurately found and re-identified*

The report map form used in CSWIP will look like the following:*

A

MEASURE FROM THIS

DATUM

E DGE

Page 1 of 3 VISUAL INSPECTION PLATE REPORT 

 Code/Specification used ________________________ Welding process _____________________ Joint type__________________ 

Name [Block capitals]__________________________ Signature ___________________________ Test piece identification

Welding position ______________________________________ Length & thickness of plate____________________ Date___________________________

Weld Face

All CSWIP 3.1 candidates should use there nominated pipe code for all your visual inspection practice, as this will help them become conversant with the specification

Practice this up and till the end of the day, or as directed by your course lecturer*