Issues regarding post-weld heat treatment of 09MnNiDR plates
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For 09MnNiDR plates with a thickness of 18 mm, what should be the temperature range for post-weld heat treatment and the duration of such treatment? How should it be determined? What is the basis? What issues should be considered when preparing weld evaluations? I saw a post from a long time ago mentioning the issue of failing the -70°C impact test.
For 09MnNiDR steel plates (commonly used in low-temperature pressure vessels), the recommended post-weld heat treatment (PWHT) parameters for a thickness of 18 mm are as follows: 1. Heat treatment temperature range: – The recommended heat treatment temperature is usually between 560°C and 620°C. 2. Heat treatment time: – The duration of heat treatment generally depends on the thickness of the steel plate and the welding energy input; as a general rule, about 1 hour of holding time is required for every 25 mm of thickness. - For a 18mm thick plate, the insulation time can be considered to be around 1 hour; however, this will need to be determined based on the actual welding energy and the specific welding process. 3. Basis for determination: – The specific parameters for heat treatment shall be determined based on the welding procedure qualification report for the 09MnNiDR material, as well as relevant standards and specifications, such as GB 3531 or ASME standards. 4. Precautions for preparing weld assessments: – Ensure that the welding materials and methods are compatible with the main material; use electrodes or wires suitable for low-temperature environments. - Thorough cleaning is carried out before welding to prevent oil, rust, or other impurities at the weld area. - Control the preheating temperature and welding heat input to avoid welding stress and deformation. - After welding, perform post-weld heat treatment promptly to eliminate welding stresses and improve the toughness of the weld area. 5. Solving the issue of failure in the -70°C impact test: – Check whether the welding process parameters meet the standard requirements. - Ensure that the post-weld heat treatment is carried out correctly, especially with regard to temperature and time control. - Consider re-evaluating the suitability and quality of the welding materials used. Please ensure that all processing steps are carried out in accordance with the latest technical specifications and standards, with relevant parameters adjusted based on specific engineering practices. .
SH 3525 might meet your above requirements. Welding specifications for low-temperature steels in petrochemical industry
1. Temperature range and time for post-weld heat treatment: For 09MnNiDR steel, the temperature range and time for post-weld heat treatment (PWHT) are typically determined based on relevant standards and the material’s properties. Here are some general recommendations: Temperature range: usually between 580°C and 620°C. Insulation time: 1 hour for every 25mm of thickness; for a thickness of 18mm, the insulation time is approximately 45 minutes to 1 hour. 2. Basis for determination: Standard basis: Refer to standards such as GB/T 150 \"Pressure Vessels\" or ASME BPVC Section VIII. Material properties: 09MnNiDR is a low-temperature steel, and it is necessary to ensure that it retains good low-temperature toughness after heat treatment. 3. Precautions for preparing weld evaluation documents Welding procedure qualification (WPS/PQR): Ensure that the welding procedure qualification meets standard requirements and covers all welding parameters. Impact test: Special attention is paid to the -70°C impact test to ensure that the low-temperature toughness of the welds and heat-affected zones meets the required standards. Preheating and interlayer temperature control: To prevent cold cracks, the preheating temperature is generally between 100°C and 150°C. Welding material selection: Choose a welding material that is compatible with the base material, to ensure consistency in chemical composition and mechanical properties. Heat treatment control: Strictly control the heat treatment temperature and time to avoid overheating or underheating. 4. Solutions for failing the -70℃ impact test: Optimize the welding process by adjusting welding parameters such as heat input, preheating, and interpass temperature. Welding material selection: Choose a welding material with better toughness. Heat treatment adjustment: Optimize the heat treatment process to ensure uniform microstructure. Weld design: Improve the weld design to reduce stress concentration. 5. Conclusion: When conducting the welding procedure qualification for 09MnNiDR steel, it is necessary to strictly control the welding and heat treatment parameters to ensure low-temperature toughness. The issue of failing the -70°C impact test can be resolved by optimizing the manufacturing process and material selection.
Hello, are there any recommended welding process parameters? Current, voltage, and welding speed during welding. For arc welding, Hawa’s W7O7Ni electrode was used; for TIG welding, Hawa’s wire HSO9HnNiDR was selected. For submerged arc welding, the same products from Hawa, namely HO9MnNiDR/SJ208DR, were used as both wire and flux. The weld pattern follows the recommended weld forms specified in HG/T 20583-2020.
Information on Harbin Wil Welding Research Institute can be found.
Thank you. Where did you find this information?
Welding of 09MnNiDR low-temperature steel for methanol plants – Research paper
Welding Procedure Qualification of 09MnNiDR Low-Temperature Steel – Thesis