weld joint preparation (iso 9692) -...

Weld Joint Preparation (ISO 9692)

Edge Preparation - Need

Poor penetration

Poor strength

Good penetration

Good strength (100% joint efficiency)

Edge PreparationFactors which influence choice of edge preparation

- Thickness- Material- Welding process- Extent of penetration required- Welding distortion- Cost

Basic Joint Types

butt

teelap

corneredge

Basic Weld TypesGroove welds

Fillet weldPlug / slot weld

Spot / seam weld

Applicable Welds for Butt jointSquare Groove weld V Groove weld

U Groove weldBevel Groove weld

J Groove weld

Applicable Welds for Butt joint

Double V Groove weld

Double U Groove weld

Double Bevel Groove weld

Double J Groove weld

Applicable Welds for Tee joint

Applicable Welds for Lap joint

Plug / slot weld Spot / seam weld

Fillet weld

Applicable Welds for Corner Joint

Applicable Welds for Edge Joint

Edge weld

Butt joint

Square Groove weld

Root gap

Butt jointSingle V Groove weld

Groove angle α

Root face

Root gap

Weld Reinforcement

Correct reinforcement

Minimum cost

Good joint strength

Excess reinforcement

High cost

Poor joint strength

Under reinforcement

Poor joint strength

Butt joint – Complete Joint penetration

Weld from face side

Back gouging

Back weld

Butt joint – Complete Joint penetration

Backing weld

Back gouging

Butt joint – Complete Joint penetration (welding from one side)

TIG / SMAW welding

Consumable guide

Butt Joint – Double V grooveLess weld metal

Less distortion

Higher edge preparation cost

Better for thickness > 20 mm

More weld metal

More distortion

Lower edge preparation cost

Better for thickness < 20 mm

Double V groove

Single V groove

Butt Joint – U groove

Good access at the root

Less weld metal

Higher edge preparation cost

Better for thickness > 40 mm

Groove angle

Root faceRoot gap

Root radius

Butt Joint – Bevel groove

Double bevel groove

Single bevel groove Bevel angle 40 to 50°

Difficult to approach the root

Weld defects

Back gouging to remove root defects

Good weld quality

Butt Joint – J groove

Good access at the root

Back gouging and back welding to get good weld quality

Less weld metal

Higher edge preparation cost

Better for thickness > 40 mm

Tee Joint – Full strength joint

leg

leg throat

throat = 0.707 x leg

leg = 1.414 x throat

In a full strength joint, leg = 0.75 x thickness

Tee Joint – Full penetration joint

leg = throat leg = throat

45° or 60°

Tee Joint

Theoretical throatActual throat

AWS D 1.1 recommendation when gap > 1.6 mm –to increase leg size of fillet by the amount of gap

Lap Joint

AWS D 1.1 recommendation

Overlap = 5 x thickness (1 inch minimum)

Gap between mating faces = 1.6 mm max

overlap

Welding Position – Groove1 G

2 G

3 G

4 G

Welding Position – Groove

1 G 2 G

5 G 6 G

45°

Welding Position – Fillet

1F

2F3F

4F

Welding Position – Fillet1F

2F

5F

Welding Positions – Groove

Position Inclination of axis Rotation of face

Flat 0° to 15° 150° to 210°

Horizontal 0° to 15° 80° to 150°

210° to 280°

Overhead 0° to 80° 0° to 80°

280° to 360°

Vertical 15° to 80° 80° to 280°

80° to 90° 0° to 360°

Welding Positions – Fillet

Position Inclination of axis Rotation of face

Flat 0° to 15° 150° to 210°

Horizontal 0° to 15° 125° to 150°

210° to 235°

Overhead 0° to 80° 0° to 125°

235° to 360°

Vertical 15° to 80° 125° to 235°

80° to 90° 0° to 360°

Joint preparation

According to ISO 9692Welding and allied processes -Recommendations for joint preparation

Part 1: Manual metal-arc welding, gas shielded metal-arc welding, gaswelding, TIG welding and beam welding of steels