PWHT – Post Weld Heat Treatment
Professional heat treatment after welding
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Post-weld heat treatment (PWHT) refers to the controlled heat treatment of a component after welding. The aim of post-weld heat treatment is to specifically reduce residual stresses created by the welding process and to ensure the required material properties of the welded component.
GRUBE GmbH, a company specializing in heat and annealing technology, has been providing professional heat treatment of welds and components for over 50 years.
With high-performance plant technology, experienced specialists and resistance and induction annealing processes, we carry out demanding PWHT heat treatments for industrial plants, power plants, pipelines, tanks and other welded structures.
National and international – stationary or directly on site.
What is Post Weld Heat Treatment (PWHT)?
Welding creates thermal stresses in the material due to the locally very high temperatures and subsequent cooling. At the same time, the material's properties can change, particularly in the weld area and the heat-affected zone.
PWHT – Post Weld Heat Treatment – addresses this issue directly.
The component, or rather the defined area around the weld, is heated in a controlled manner according to a predetermined temperature-time profile. Once the specified treatment temperature is reached, it is maintained for a defined period. Controlled cooling then follows.
Depending on the material, component, wall thickness and technical requirements, the parameters of the heat treatment are individually determined.
Why is PWHT necessary?
Properly performed heat treatment after welding can be crucial for the properties and long-term operational reliability of a component.
PWHT can be used in particular to:
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To reduce residual stresses in welding,
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to reduce high hardness values in critical areas,
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to influence the ductility and toughness of the material,
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to reduce the risk of certain types of cracking,
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to support dimensional and shape stability and
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to achieve the material properties required for the respective component or set of regulations.
The required heat treatment always depends on the material, design, welding process, wall thickness, operating conditions and the applicable technical specifications.
PWHT with resistance heating
In electrical resistance heating, suitable heating elements are attached directly to the component to be treated or in the area of the weld seam.
The heat is introduced into the component in a targeted manner and controlled via measurement and control technology.
This process enables precise local heat treatment and is suitable for numerous applications in pipeline, plant, power plant and tank construction.
GRUBE has high-performance mobile annealing systems, heating elements and modern measuring and control technology for this purpose.
PWHT through induction annealing
In addition to resistance heating, GRUBE offers heat treatment using induction.
In induction annealing, heat is generated electromagnetically directly within the workpiece. This allows components to be heated quickly, in a controlled manner, and efficiently.
Especially in demanding industrial applications and with large wall thicknesses, induction can be a powerful solution for preheating and heat treatment after welding.
Our experts work with the customer to select the most suitable method for the specific application.
Mobile PWHT directly on your construction site
Many welded components cannot be transported to a stationary heat treatment plant due to their size, weight, or installation situation.
Therefore, mobile PWHT on site is one of GRUBE's core competencies.
Our mobile annealing plants and systems enable controlled heat treatment directly on pipelines, tanks, plant components and other welded structures.
Our specialists are deployed nationally and internationally, supporting industrial companies even in complex projects and time-critical shutdowns.
PWHT for pipelines and pipe welds
Especially with pipelines, there can be high demands on welded joints and material properties.
GRUBE carries out the controlled heat treatment of pipe welds and piping systems according to project-specific requirements.
This includes both controlled preheating before or during the welding process and the necessary heat treatment after completion of the welding work.
PWHT for tanks and industrial plants
Heat treatment after welding may also be necessary for pressure vessels, plant components and large welded structures.
Our mobile plant technology allows heat treatments to be carried out even on large components and with complex geometric requirements.
For particularly large components, individually planned solutions and mobile furnace systems can be used – depending on the technical requirements of the project.
PWHT for power plants and petrochemicals
GRUBE has decades of experience in heat treatments in demanding industrial environments.
Our areas of operation include, among others:
Power plants and energy facilities, petrochemical and chemical industries, plant and pipeline construction, tank construction, overhauls and shutdowns, as well as industrial assembly and maintenance projects.
Especially during time-critical shutdowns, reliable planning, high-performance technology and readily available specialist personnel are crucial.
Preheating and heat treatment from a single source
Professional heat technology doesn't begin only after welding.
GRUBE already supports its customers in the preheating of welded joints and accompanies the entire thermal process up to the final post-weld heat treatment.
This provides our customers with preheating,
Interlayer temperature control, heat treatment and the associated measurement and control technology from a single source.
Controlled temperature management
Professional PWHT treatment relies on precisely controlled temperature management.
Depending on the project-specific requirements, the following parameters, among others, are taken into account:
Heating rate – Treatment temperature – Holding time – Temperature distribution – Cooling rate
Temperature sensors and professional measuring and control technology enable the monitoring of the heat treatment process.
The specific parameters are determined according to the respective material, customer, project and regulatory requirements.
PWHT according to international requirements
Industrial projects differ considerably in terms of materials, designs, and applicable regulations.
Therefore, professional post-weld heat treatment is not performed according to a standard temperature program.
GRUBE carries out heat treatments in accordance with the respective specified technical specifications, procedures and project requirements.
This makes our service suitable for demanding national and international industrial projects.
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
Your specialist for post-weld heat treatment
Do you require reliable PWHT heat treatment for welds, pipelines, tanks or industrial plants?
The team at Wärme- und Glühtechnik GRUBE GmbH supports you from the technical planning to the execution of the heat treatment on site.
Whether it's post-weld heat treatment, stress-relief annealing, preheating, resistance annealing or induction annealing – we develop a solution tailored to your project.
Request PWHT project
Speak to our specialists about the requirements of your project.
Heating and annealing technology GRUBE GmbH
Old Brickworks 1
48734 Reken
24-hour service – national and international