CON-03!03!22 Temper Bead Welding Procedure

CON 03-03-22 PROCEDURE 29 October 2008 CONSTRUCTION

Welding Procedures Temper - Bead Welding Replaces: CON 03-03-22 dated 26 July 2002

Overview This standard describes procedures for both temper-bead welding, and half-bead temper-bead welding.

Audience This standard is primarily intended for Welders, Welding Instructors, welding inspectors, welding engineers, designers, and personnel applying the technique.

Limitations These welding techniques must only to be used when specified in procedures addressing welding repairs of certain defects in pipe and components and welding of high carbon equivalent materials.

Temper-Bead Welding The basic principle of temper-bead welding is to use subsequent weld beads to temper or soften the previous weld bead. This technique reduces average weld hardness and the possibility of weld cracking. However, temper-bead welding does not reduce internal stresses within the welded joint and is not a substitute for post-weld heat treatment when required by code for service requirements.

For critical applications, low hydrogen electrodes must be used, although these principles may be applied with any electrode. Since weld metal usually has a lower carbon equivalent and is less hardenable than base metal, final weld beads should approach but not make contact with the base metal. The final weld bead must be located approximately 3 mm from the base metal. Where welding is performed on live systems and subject to rapid cooling, the final weld pass must not make contact with the carrier pipe. By using the principles of temper-bead welding, many standard weld configurations can be successfully modified.

CON-03-03-22.doc Page 1 of 6 Caution: Printed documents may not be current. Verify online.

Temper - Bead Welding

CON-03-03-22.doc Page 2 of 6

Sequencing and Dimensions of Various Weld Beads Figure 1a: Typical Sequences and Dimensions for Temper-Bead Welding

Figure 1b: Typical Sequences and Dimensions for Temper-Bead Welding

Caution: Printed documents may not be current. Verify online.



Figure 1c: Typical Sequences and Dimensions for Temper-Bead Welding

Figure 1d: Typical Sequences and Dimensions for Temper-Bead Welding




Figure 1e: Typical Sequences and Dimensions for Temper-Bead Welding

Procedure This procedure must be strictly followed to obtain the best results.

1. Clean the areas to be welded to bare metal using a wire brush, grinding wheel, or blending disc.

2. Preheat to a minimum of 100 C, where practical. 3. Deposit weld beads as suggested in Figure 1a through e. 4. Final weld deposit must not touch the base metal.

Half-Bead Temper-Bead Welding Half-bead temper-bead welding involves buttering the weld bevel with an initial layer of weld metal, after which of this layer is ground away. This isolates the base metal from the weld metal so that any subsequent welding will anneal the initial buttering pass and immediate base metal. Low-hydrogen welding processes and consumables are most often used with this technique.




Figure 2: Typical Sequence and Dimensions for Temper-Bead Welding



CON-03-03-22.doc Page 6 of 6 Caution: Printed documents may not be current. Verify online.

Procedure This procedure should be reviewed with a welding engineer or specialist prior to use.

1. Where appropriate, grind out defect and prepare bevel. 2. Inspect bevel preparation with magnetic particle inspection prior to

welding. 3. Preheat to a minimum of 100 C, where practical. 4. Deposit welded butter layer over entire bevel surface extending

beyond top of bevel (see figure 2a). 5. Grind away 50% of the thickness of butter layer. 6. Deposit a second weld layer over top of the butter layer keeping the

edge of the deposit approximately 3 mm from the base metal (see figure 2b).

7. Deposit balance of weld beads using temper-bead welding sequence ensuring that no weld pass touches the base metal (see figure 2c).

8. Allow the weld to cool. In situations involving pipe stress other than internal hoop stress,

low ambient temperatures, higher or unknown carbon equivalent steels, or a high cooling rate, after completion of the welding keep the weldment warm for a longer period by heating with a torch or wrapping the pipe with an insulating material.

9. Inspect with magnetic particle inspection after the weld has cooled. It is recommended that a magnetic particle inspection is not done until 48 hours has passed.
OverviewAudienceLimitationsTemper-Bead WeldingSequencing and Dimensions of Various Weld BeadsProcedureHalf-Bead Temper-Bead WeldingProcedure

CON-03!03!22 Temper Bead Welding Procedure

Documents

Transcript of CON-03!03!22 Temper Bead Welding Procedure