PWHT cost for pipe welding depends mainly on pipe diameter, wall thickness, material, heating method and the code you must follow. There is no single price per joint, and contractors usually quote per joint, per hour or as a lump sum for the job. Always ask for a quote based on your actual pipe schedule and procedure.
This guide explains what PWHT (post weld heat treatment) is, when it is required, and what drives the price, so you can compare quotes.
What Is PWHT in Pipe Welding?
PWHT is a controlled heating, holding and cooling cycle applied to a welded joint. It relieves residual stress and can soften hard zones, which lowers the risk of cracking in service. It is common on thick-wall carbon steel and on alloy steels such as chrome-moly.
When Is PWHT Required?
The piping code or project specification decides. For example, ASME B31.3 process piping generally requires PWHT for carbon steel (P-No. 1) above a set wall thickness, with a holding time of about one hour per 25 mm of thickness and a 15-minute minimum. Many alloy steels need PWHT at much thinner walls. Check the code edition and your welding procedure for the exact limits.
What Drives PWHT Cost for Pipe Welding
| Cost factor | Why it matters |
|---|---|
| Pipe diameter | Larger pipe needs more heating coverage and sometimes several control zones. |
| Wall thickness | Thicker walls need longer holding times and slower ramp rates. |
| Material | Alloy steels need tighter temperature control and higher holding temperatures. |
| Heating method | Induction, electric resistance and gas flame differ in setup time, speed and control. |
| Number of joints | Many joints spread mobilisation and setup costs. |
| Documentation | Thermocouple charts and records add time, especially on code work. |
| Site conditions | Access, weather, insulation needs and travel add labour. |
Heating Methods Compared
- Induction: fast and even, good for large jobs and many joints, with higher equipment cost.
- Electric resistance: flexible for odd shapes such as elbows and branches, common for shop and field work.
- Gas flame: simple for remote sites, but harder to control and document, so it is not accepted by every specification.
How to Get an Accurate PWHT Quote
- Give the pipe size, schedule, material and number of joints.
- State the code and the required temperature and hold time.
- Say whether the job is in the shop or in the field.
- Ask what is included: heating equipment, insulation, thermocouples, charts and travel.
- Compare at least two quotes on the same scope.
Ways to Reduce PWHT Cost
- Check whether your procedure and code actually require PWHT, or whether preheat or a different material avoids it.
- Group joints so they can be treated in one mobilisation.
- Keep the welding quality high. Weld repairs mean repeated heat treatment.
- Plan insulation and thermocouple placement in advance.
For related pricing, see our guides on pipe welding rates, how to calculate pipe welding cost and the general welding cost guide.
Frequently Asked Questions
What does PWHT cost for pipe welding?
There is no standard price. Contractors quote per joint, per hour or as a lump sum based on pipe size, wall thickness, material, heating method and code requirements.
What is PWHT?
Post weld heat treatment is a controlled heating, holding and cooling cycle that relieves residual stress and softens hard zones in a welded joint.
When is PWHT required on pipe?
When the governing code or specification says so. It depends on material and wall thickness, so check the code edition and your welding procedure.
Which PWHT heating method is best?
Induction is fast and even for large jobs, resistance heating suits complex shapes, and gas flame suits remote sites but is harder to control.
