Position Welding Joint and Types

"All position welding" refers to welding that can be performed in all positions (flat, horizontal, vertical, and overhead) on plate and pipe joints. These joints are commonly used in structural steel, pipelines, pressure vessels, and shipbuilding. Below are the welding joint types and positions typically used for plate welding, along with their details.

🔧 Common Welding Joint Types for Plate Welding

Joint Type,Description and Common Use

Butt Joint :- Two plates in the same plane Pipe & structural welding

Tee Joint :- One plate perpendicular to another Fillet welds

Lap Joint :-One plate overlaps the other Sheet metal & automotive

Corner Joint :-Plates meet at a corner (L-shape) Box structures, frames

Edge Joint :-Plates are side-by-side with edges touching Sheet metal, tanks

📐 Welding Positions for Plate Welding

Welding positions are classified according to plate orientation and welding direction. These are covered in ASME and AWS (American Welding Society) standards.

Position, Code and Description.

Flat :- 1G / 1F Plate is flat; weld made from above

Horizontal :- 2G / 2F Plate vertical; weld horizontal

Vertical :- 3G / 3F Plate vertical; weld runs vertically up/down

Overhead :- 4G / 4F Plate above the welder; weld made from below

G = Groove weld

F = Fillet weld

📄 Detailed Joint & Position Examples

Joint Type, Position, Weld Type & Typical Use

Butt Joint :- 1G (Flat) Groove High-strength joints, easy access

Tee Joint :- 2F (Horizontal) Fillet Structural frames

Corner Joint :- 3G (Vertical) Groove Tank corners, box structures

Lap Joint :- 4F (Overhead) Fillet Automotive panels

Edge Joint :- 1G–3G Groove or fillet Pressure vessels, tanks

🧪 Additional Considerations

WPS (Welding Procedure Specification) required for each joint and position.

Preheat/Postheat treatment may be required based on thickness/material.

Back gouging/backing strip used in some full penetration welds (especially in butt joints).

Testing (NDT, visual, bend tests) is often required, especially for certification or structural work.

✅ Summary

To weld plate in all positions, a welder must be proficient in:

Multiple joint types (butt, tee, lap, etc.)

All positions (1G to 4G / 1F to 4F)

Using various processes: SMAW, GMAW, FCAW, TIG

Reading WPS and understanding weld symbols.