Weld repair of low alloy creep resistant steel castings without preheat and post-weld heat treatment

1986 ◽  
Vol 22 (3) ◽  
pp. 161-176 ◽  
Author(s):  
J.N. Clark
Keyword(s):  
Heat Treatment ◽  
Post Weld Heat Treatment ◽  
Resistant Steel ◽  
Weld Repair ◽  
Steel Castings ◽  
Weld Heat

scholarly journals Improvement in Weldment of Dissimilar 9% CR Heat-Resistant Steels by Post-Weld Heat Treatment

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1321
Author(s):  
Jiankun Xiong ◽  
Ting Li ◽  
Xinjian Yuan ◽  
Guijun Mao ◽  
Jianping Yang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Surface ◽  
Weld Metal ◽  
Critical Power ◽  
Post Weld Heat Treatment ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Heat Resistant Steels ◽  
Weld Heat

The effect of the post-weld heat treatment on the microstructures and mechanical properties of the dissimilar joint of G115, a novel developed martensite heat resistant steel, and CB2 steel, currently used in an ultra-super-critical power unit, was investigated. The results indicate that the quenched martensite underwent decomposition and transformation, and the amount of dislocations were sharply decreased in the weld metal after post-weld heat treatment (PWHT). Many nano-scale M23C6 precipitates present in the weldment were distributed on the grain and grain boundary in a dispersed manner with PWHT. The average microhardness of the weldment decreased from about 400 HV to 265–290 HV after PWHT and only a slight decrease in the microhardness of CB2 steel was detected after PWHT at 760 °C. In contrast to the case of the as-received joint, the tensile strength of the joint was improved from 630 MPa to 694 MPa and the fracture location moved from the weld metal to the base metal after PWHT. The fracture surface consisted of a cleavage fracture mode without PWHT, whereas many dimples were observed on the fracture surface with PWHT.

Effect of Pipe Length on the Temperature Field for 9% Cr Heat-Resistant Steel Pipes in Local Post Weld Heat Treatment

2019 ◽  
Vol 953 ◽  
pp. 32-38
Author(s):  
Xi Wang ◽  
Jiao Zhong ◽  
Hao Ke
Keyword(s):  
Heat Treatment ◽  
Temperature Field ◽  
Outer Wall ◽  
Post Weld Heat Treatment ◽  
Resistant Steel ◽  
Pipe Length ◽  
Heat Resistant Steel ◽  
Steel Pipes ◽  
Heat Resistant ◽  
Weld Heat

ANSYS was used to establish the calculation model of the temperature field for 9% Cr heat-resistant steel pipes in local post-weld heat treatment (PWHT). And the computation model has been validated experimentally. Based on the numerical model, the temperature field distribution was simulated for different pipe lengths in local PWHT, and effects of pipe length on the temperature distribution of heat treatment was further studied. Results show that increase of pipe length has little influence on equivalent temperature measurement point, soak band (SB) width of outer wall and axial temperature gradient, while it causes temperature difference between outer and inner wall to increase and soak band width to reduce significantly in inner wall. And when pipe length increases to a certain extent, the temperature field tends to be stable gradually.

Integrity Analysis of a Vessel Subject to Weld Repair and Post-Weld Heat Treatment: Thermal Stress Distribution Using Numerical Approach

2020 ◽  
Vol 1000 ◽  
pp. 348-355
Author(s):  
Ardiyansyah Yatim ◽  
Gatot Prayogo ◽  
Ahmad Karayan ◽  
Hendra Novi ◽  
Wildan Hamdani ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Welding Process ◽  
Numerical Approach ◽  
Post Weld Heat Treatment ◽  
Thick Wall ◽  
Weld Repair ◽  
Element Analysis ◽  
Small Deflection ◽  
Integrity Analysis ◽  
Weld Heat

Here, we present a numerical approach to analyze the integrity of a vessel that was subject to a weld repair. A Post-Weld Heat Treatment (PWHT) process was implemented to a vessel undergone weld repair due to leakage. Due to the thick wall of the welded bottom head, this welding process must be followed by the PWHT to relieve the residual stress, as well as to improve the material properties. PWHT process was performed by heating the welded area to reach 675 °C temperature. A numerical approach using finite element analysis (FEA) method was performed to analyze the integrity of the vessel. Based on the analysis, the structure is still stable within the applied load. PWHT process does not lead to buckling on the main structure and the load is still lower than the load required for the occurrence of buckling. A sensitivity analysis was also performed with reduced temperatures to 630 °C or reduction of PWHT area width. These changes were found to have negligible effects in reducing the stress and strains in the vessel. After PWHT is completed, the structure is still considered to be safe to be operated, as indicated by its strain that is still below the allowable strain and only relatively small deflection was occurred.

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