ASME & AWS Compliant P91 Heat Treatment Services

P91 is one of the most demanding materials in the industry, it requires pre- planning, finite temperature control and execution to get it right. At AxiomHT, we believe that properly executed P91 heat treatment controls cost, maintains schedules, and avoids rework.

Full-scope P91 execution for refineries, power plants & industrial facilities

We support projects in power generation, oil refineries, chemical plants, fabrication, manufacturing and industrial facilities.

Preheat Bake Out and Post Weld Heat Treatment (PWHT)

Digital Temperature Control and Monitoring

Complete Project Planning From Contract Through Completion

Compliance That Meets or Exceeds Current Industry Standards

QA/QC Management Support And Documentation

What Sets AxiomHT Apart To Ensure P91 Project Success

With Over 150 Years Of Executive Leadership, AxiomHT also provides:

P91 Certified Project Managers Supervision and Technicians (An Industry First)

A Dedicated Project Leader With Over 25 Years Of P91 Experience

Precise Planning, Cost, Schedule, Monitoring and Reporting

Pre-Job QA/QC Alignment (Code & Execution)

P91 Heat Treatment Risk Mitigation Sessions

P91 is unforgiving, “P91 does not forgive or forget bad heat treatment.”

CEO Gerry McWeeney.

Partner with AxiomHT!

Contact AxiomHT today to discuss your P91 project.

What Is P91 Heat Treatment?

P91 is a high-strength, creep-resistant alloy used in high-temperature, high-pressure applications—commonly found in power plants and refineries.

Heat treatment for P91 is critical to ensure:

Proper microstructure

Long-term strength

Resistance to creep and cracking

P91 requires tight control over:

Thermocouple placement

Heated band widths

Temperature control during heating & cooling

Time at temperature

Why It Matters

Improper heat treatment can lead to:

Premature failure

Cracking under stress

Expensive downtime and repairs

Unlike standard materials, P91 requires tight control over:

Thermocouple placementaterial properties

Heated Band Widths

Temperature Control During Heating & Cooling

Time at temperature

Key Steps in P91 Heat Treatment

1

Preheat Before & During Welding

Establish correct base temperature to prevent cracking.

2

Hydrogen Bake Out

Remove diffusible hydrogen from the weld area.

3

Controlled PWHT Cycle

Execute the full post weld heat treatment cycle to spec.

4

Uniform Heating

Maintain consistent temperature across the entire weld zone.

5

Controlled Cooling

Bring the material down at the correct rate to lock in properties.

6

Documentation

Every step recorded to meet code and performance requirements.

Need help planning P91 heat treatment?

Contact AxiomHT for expert support.

Common P91 Heat Treatment Failures

Most P91 failures do not happen immediately. They show up months later during operation. Here are the most common causes:

Poor Temperature Control

Uneven heating leads to inconsistent material properties which can create short- and long-term risk.

Incorrect Thermocouple Placement

Without proper monitoring, hot spots and cold zones go unnoticed.

Inadequate Band Widths

Sharp gradients introduce stress and instability in the material.

Improper Cooling

Cooling too quickly or unevenly can undo proper heat treatment.

Lack of Planning

Many issues start before the job begins — with incomplete setup, quality, and planning coordination.

How to Avoid These Issues

Plan Heat Treatment Early

Start planning before the first heater is installed.

Use Proper Monitoring

Deploy real-time control and monitoring across the cycle.

Align HT + QA/QC

Coordinate with planning and construction groups.

How to Plan P91 Heat Treatment

Successful P91 heat treatment starts long before the first heater is installed. Planning is what determines cost, schedule, and quality.

Key Planning Steps

1. Define Scope Clearly
Identify welds, thickness, and code requirements up front.

2. Align Teams Early
Welding, QA/QC, and heat treatment must be coordinated.

3. Plan Equipment and Monitoring
Ensure enough capacity for control—not just coverage.

1. Define Scope Clearly
Setup often takes longer than the heat cycle itself.

Improper heat treatment can lead to:

Delays

Rework

Increased costs

Strong planning leads to:

Predictable execution

Controlled outcomes

On-time completion

Your P91 Heat Treatment Partner

If you are looking for a reliable P91 heat treatment company, AxiomHT delivers the experience and execution your project needs.

We Provide

Full on-site field heat treatment services — Resistance, Induction & Combustion

Furnace and controlled heating solutions

Less heating elements

Code-compliant execution

Serving Industries

Refineries Power Generation Fabrication Shops Industrial Facilities

Why Clients Choose AxiomHT

Commitment to schedule and cost management

Ability to support complex projects

Strong focus on quality and control

Proven track record

Ready to discuss your project?

Contact AxiomHT today to discuss your project and get started.