Materials and Heat Treatment – PWHT
Professional heat treatment for the highest material requirements
The heat treatment of metallic materials is a crucial component of industrial manufacturing, plant construction, and maintenance. Different steel alloys require individually tailored temperatures and treatment processes to ensure their mechanical properties, strength, and long-term operational reliability.
The GRUBE GROUP offers professional solutions for preheating, tempering, stress-relief annealing and post-weld heat treatment (PWHT).
In doing so, we take into account the specific requirements of different materials – from unalloyed pressure vessel steels to heat-resistant chromium-molybdenum steels and high-alloy power plant steels.
What does PWHT mean?
PWHT stands for Post Weld Heat Treatment and refers to the controlled heat treatment of components after welding.
By selectively heating, holding and cooling, welding residual stresses can be reduced, critical microstructures can be influenced and the required material properties can be adjusted.
Especially with high-temperature resistant steels, thick-walled pressure vessels, pipelines and safety-relevant plant components, professional heat treatment is of great importance.
Materials overview
Below you will find the various materials with their material numbers, the specified heat treatment temperatures, the possible treatment methods, as well as their typical properties and areas of application.
Important technical note: The temperatures mentioned are non-binding guidelines from the provided material overview and not generally applicable target temperatures. The respective approved heat treatment instructions, material standards, and project-specific specifications are binding.
1. Heat-resistant and high-alloy steels
These materials are used particularly in power plant construction, steam systems, boiler construction and in thermally stressed industrial plants.
13CrMo4-5 – Material number 1.7335
Temperature according to overview: 680 °C - Glowing temperature ±10 °C*
Heat treatment: Preheating, tempering and PWHT
13CrMo4-5 is a heat-resistant, low-alloy chromium-molybdenum steel with good resistance to elevated operating temperatures. It is frequently used for boilers, pressure vessels, and pipelines in thermally stressed industrial plants.
10CrMo9-10 – Material number 1.7380
Temperature according to the overview: 720 °C - annealing temperature ±10 °C*
Heat treatment: Preheating, tempering and PWHT
10CrMo9-10 is an alloy steel for high-temperature piping, steam systems, and pressure vessels. The alloying elements chromium and molybdenum improve its high-temperature strength and creep resistance.
11CrMo9-10 – Material number 1.7383
Temperature according to the overview: 715 °C - annealing temperature ±10 °C*
Heat treatment: Tempering and PWHT
Heat-resistant chromium-molybdenum steel for thermally stressed plant components. The material designation and its standard classification must be verified using the material certificate.
X10CrMoVNb9-1 (P91) – Material number 1.4903
Temperature according to the overview: 765 °C - annealing temperature ±10 °C*
Heat treatment: preheating, intermediate cooling, tempering and PWHT
P91 is a martensitic, high-temperature steel with vanadium and niobium additives. It is particularly suitable for high-temperature steam lines and power plant components. Controlled heat input after welding is crucial for achieving the required microstructure and long-term strength.
X10CrWMoV9-2 (P92) – Material number 1.4901
Temperature according to overview: 765 ° C - Incandescence temperature ±10 °C*
Heat treatment: preheating, intermediate cooling, tempering and PWHT
P92 is an advanced martensitic power plant steel containing tungsten, molybdenum, vanadium, and niobium. It was developed for demanding high-temperature applications and is characterized by improved creep resistance.
X11CrMoWVNb9-1-1 – Material number 1.4905
Temperature according to the overview: 765 °C - annealing temperature ±10 °C*
Heat treatment: PWHT
This heat-resistant martensitic steel contains chromium, molybdenum, tungsten, vanadium, and niobium. It is used for high-temperature components where controlled microstructure development and high creep rupture strength are required.
X12CrMo9-1 – Material number 1.7386
Temperature according to overview: 715 °C - Glowing temperature ±10 °C*
Heat treatment: Preheating and PWHT
Heat-resistant alloy steel for thermally stressed piping and plant components. The exact material classification and heat treatment requirements must be confirmed according to the respective specification.
X20CrMoV12-1 (X20) – Material number 1.4922
Temperature according to the overview: 760 °C - annealing temperature ±10 °C*
Heat treatment: preheating, intermediate cooling, tempering and PWHT
X20 is a martensitic, high-temperature-resistant steel used particularly in high-pressure steam lines, power plants, and turbine environments. Controlled heat treatment is crucial for achieving the required microstructure.
12CrMo19 5 – Material number 1.7263
Temperature according to the overview: 740 °C - annealing temperature ±10 °C*
Heat treatment: According to approved heat treatment instructions
Alloyed heat-resistant steel for components with increased thermal requirements. Before determining the treatment parameters, the exact material designation must be checked against the applicable standard.
14MoV6-3 – Material number 1.7715
Temperature according to the overview: 705 °C - annealing temperature ±10 °C*
Heat treatment: According to approved heat treatment instructions
14MoV6-3 is a heat-resistant steel for boiler components, steam lines, and pressurized plant components. Its alloy composition enhances its strength at elevated temperatures.
15CrMoV5 10 – Material number 1.7745
Temperature according to overview: 730 ° C - Glowing temperature ±10 °C*
Heat treatment: According to approved heat treatment instructions
Heat-resistant alloy steel for mechanically and thermally demanding components. The exact material designation, the delivery condition, and the required heat treatment condition must be verified before use.
7CrMoVTiB10-10 – Material number 1.7378
Temperature according to the overview: 740 °C - annealing temperature ±10 °C*
Heat treatment: According to approved heat treatment instructions
This chromium-molybdenum-vanadium steel also contains titanium and boron. It is designed for applications with increased requirements for high-temperature strength, creep resistance, and long-term operational reliability.
HCM 12 – Material number not uniquely assigned
Temperature according to the overview: 750 °C - annealing temperature ±10 °C*
Heat treatment: According to precise material specifications
HCM 12 designates a family of materials for power plant components subjected to high temperatures. The exact material variant and its properties must be clearly determined before the heat treatment parameters are defined.
2. High-strength and alloyed pressure vessel steels
These materials are used in thick-walled pressure vessels, demanding welded constructions and safety-relevant plant components.
11NiMoV5 3 – Material number 1.6341
Temperature according to overview: 570 °C - Incandescence temperature ±10 °C*
Heat treatment: Material-dependent heat treatment
Low-alloy, high-strength steel for demanding pressure vessels and thick-walled components. The heat treatment must be carefully controlled to maintain the required strength and toughness.
15NiCuMoNb5-6-4 – Material number 1.6368
Temperature according to the overview: 585 °C - annealing temperature ±10 °C*
Heat treatment: Preheating and PWHT according to released instructions
Precipitation-hardening steel with high strength and toughness. It is used, among other things, for demanding pressure vessels. Heat treatment influences the mechanical properties and must be carefully tailored to the specific delivery condition.
12MnNiMo5-5 – Material number 1.6343
Temperature according to the overview: 570 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
Alloy steel for pressure-loaded and thick-walled components. The combination of its alloying elements promotes high strength and good toughness. Controlled stress-relief annealing can reduce manufacturing-related residual stresses.
13MnNiMo5-4 – Material number 1.8807
Temperature according to the overview: 570 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
High-strength steel for pressure vessels and safety-relevant plant components. Controlled heat treatment serves to reduce residual welding stresses while taking into account the required material properties.
3. Boiler and pressure vessel steels
This group of materials is frequently used in industrial plant engineering, energy production and in pressure-bearing structures.
16Mo3 – Material number 1.5415
Temperature according to overview: 585 °C - Incandescence temperature ±10 °C*
Heat treatment: Stress-relief annealing
16Mo3 is a readily weldable, heat-resistant steel for steam boilers, heat exchangers, pressure vessels, and piping. Due to its molybdenum alloy, it is suitable for applications with elevated operating temperatures.
P195GH – Material number 1.0348
Temperature according to the overview: 560 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P195GH is a steel with defined properties for pressure and temperature stresses. Typical applications include boiler systems, pipelines, and pressure-bearing industrial components.
P275NH – Material number 1.0487
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P275NH is a weldable fine-grained steel with good toughness properties. It is used particularly for pressure vessels and demanding welded structures.
P235GH – Material number 1.0345
Temperature according to the overview: 560 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P235GH is a readily weldable steel for pressure vessels, steam boilers, and thermally stressed components. It is frequently used where reliable pressure resistance is required with moderate strength requirements.
P250GH – Material number 1.0460
Temperature according to overview: 570 °C - Glowing temperature ±10 °C*
Heat treatment: Stress-relief annealing
Steel for pressure-loaded components in industrial plant engineering. The specific product standard and the delivery condition must be checked before determining the heat treatment.
P265GH – Material number 1.0425
Temperature according to the overview: 560 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P265GH is a widely used, readily weldable pressure vessel steel. It is used for tanks, boilers, heat exchangers, and industrial piping systems.
P295GH – Material number 1.0481
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P295GH is suitable for pressure- and temperature-stressed vessels and system components. It is used particularly when higher strength requirements exist compared to simpler pressure vessel steels.
P355GH – Material number 1.0473
Temperature according to the overview: 560 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P355GH is a pressure vessel steel with an increased yield strength. Typical applications include boilers, tanks, and piping components. Heat treatment is necessary to maintain the specified mechanical properties.
P355NH – Material number 1.0565
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P355NH is a weldable, fine-grained pressure vessel steel with high strength and good toughness. It is suitable for demanding pressure vessel designs and welded plant components.
P420NH – Material number 1.8932
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P420NH is a high-strength pressure vessel steel for mechanically demanding designs. Particular attention must be paid to strength and toughness requirements during heat treatment.
P460NH – Material number 1.8935
Temperature according to the overview: 555 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P460NH is a high-strength steel for heavily stressed pressure vessels. Heat treatment parameters must be carefully tailored to the material condition and applicable requirements.
4. Pipeline and structural steels
These materials are used in industrial piping systems, steel construction, and welded plant structures.
API 5L Grade X65
Temperature according to overview: 580 °C - Glowing temperature ±10 °C*
Heat treatment: Stress-relief annealing
16Mo3 is a readily weldable, heat-resistant steel for steam boilers, heat exchangers, pressure vessels, and piping. Due to its molybdenum alloy, it is suitable for applications with elevated operating temperatures.
C 22.3 – Material number 1.0427
Temperature according to the overview: 570 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P195GH is a steel with defined properties for pressure and temperature stresses. Typical applications include boiler systems, pipelines, and pressure-bearing industrial components.
St 35.8 – Material number 1.0305
Temperature according to the overview: 560 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P275NH is a weldable fine-grained steel with good toughness properties. It is used particularly for pressure vessels and demanding welded structures.
WStE 255 – Material number 1.0462
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P235GH is a readily weldable steel for pressure vessels, steam boilers, and thermally stressed components. It is frequently used where reliable pressure resistance is required with moderate strength requirements.
WStE 315 – Material number 1.0506
Temperature according to overview: 565 °C - Incandescence temperature ±10 °C*
Heat treatment: Stress-relief annealing
Steel for pressure-loaded components in industrial plant engineering. The specific product standard and the delivery condition must be checked before determining the heat treatment.
WStE 380 – Material number 1.8930
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
P265GH is a widely used, readily weldable pressure vessel steel. It is used for tanks, boilers, heat exchangers, and industrial piping systems.
ASTM A333 Grade 6 – Material number
Temperature according to the overview: 565 °C - annealing temperature ±10 °C*
Heat treatment: Stress-relief annealing
ASTM A333 Grade 6 is a carbon steel for seamless and welded tubes in low-temperature applications. Particular attention must be paid to achieving the required impact toughness during heat treatment.
Why is proper heat treatment crucial?
Every material possesses specific mechanical and metallurgical properties. Inappropriate heat treatment can impair the strength, toughness, and long-term service life of a component.
Therefore, in particular, the treatment temperature, holding time, and heating and cooling rate must be tailored to the material and the specific application.
Your advantages with the GRUBE GROUP
Material-appropriate heat treatment: Individual adaptation to material, component geometry and technical requirements.
Controlled temperature management: Targeted heating, holding and cooling according to predefined parameters.
Industrial applications: Solutions for power plants, refineries, chemical plants, piping systems and pressure vessel construction.
Quality and traceability: Implementation based on the respective technical specifications and documentation requirements.
Preheating and PWHT from a single source
Preheating often doesn't end with the final welding pass in demanding welding tasks.
Depending on the material, wall thickness and technical specifications, further heat treatment may be necessary after completion of the welding work.
GRUBE therefore combines Pre-Heating and Post Weld Heat Treatment (PWHT) into a comprehensive heat treatment concept.
This enables a controlled process from the preparation of the welding point through preheating and monitoring of the welding process to the subsequent heat treatment.
PRE-HEATING → WELDING → PWHT
One contact person for the entire thermal process.
Preheating directly on your construction site
Our systems are designed for mobile use. This allows heat treatments to be carried out directly where welding is taking place.
Whether it's a power plant, refinery, petrochemical plant, pipeline project, tank construction or industrial overhaul – our teams and facilities can be deployed on-site on a project basis.
Even components that are difficult to access and complex geometries can be processed with appropriately adapted heating and insulation concepts.
More than 50 years of experience in heat treatment
Since 1974 , Wärme- und Glühtechnik GRUBE GmbH has stood for professional industrial heat treatment.
Today, our experience is combined with modern plant, measurement and control technology as well as a highly qualified team.
Our customers benefit from:
More than 50 years of experience · international project experience · mobile PWHT · resistance annealing · induction annealing · mobile annealing furnaces · high-performance measurement and control technology · qualified specialists · 24-hour personnel service
Experience, technology and controlled processes
Professional preheating means more than simply heating a component.
Crucial factors are the right heating technology, suitable positioning of the heating elements, sufficient insulation, and controlled and traceable temperature management.
GRUBE combines many years of experience in industrial heat treatment with high-performance technology and flexible solutions for a wide variety of operating conditions.
Your project. Our heat treatment.
Do you need assistance with preheating pipes, containers, or other components before welding?
Speak to our specialists.
Together we develop a suitable solution for material, component geometry, welding process and the respective project requirements.
