Effect of postweld heat treatment on interface microstructure and metallurgical properties of explosively welded bronze—carbon steel

2018 ◽  
Vol 25 (8) ◽  
pp. 1849-1861 ◽  
Author(s):  
Mohammad Reza Khanzadeh Gharahshiran ◽  
Ali Khoshakhlagh ◽  
Gholamreza Khalaj ◽  
Hamid Bakhtiari ◽  
Ali Reza Banihashemi
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Postweld Heat Treatment ◽  
Interface Microstructure ◽  
Metallurgical Properties ◽  
Postweld Heat

PWHT Exemptions for Carbon Steel in B31.3: An EPC Contractor’s Perspective

2020 ◽  
Author(s):  
Jan-Willem Rensman ◽  
George Kraayeveld
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Postweld Heat Treatment ◽  
Steel Pipe ◽  
Postweld Heat

Abstract In the 2014 edition of the ASME B31.3 Code [1], thick, P-No. 1 carbon steel pipe became exempt from Postweld Heat Treatment (PWHT) under the condition of preheating at 95°C (200°F) and multi-pass welding. The decision whether to apply PWHT or not is left to the designer but no further guideline is provided. The impression is that the need for PWHT is only corrosion/service related, and not beneficial or necessary for the integrity of the piping. Several publications [2][3][4] have addressed these changes and highlighted that this might lead to potentially unsafe situations. This paper will critically review the arguments used for the justification of the PWHT exemption for carbon steel and show that many arguments are invalid or incomplete. It will discuss the implications for the performance of materials and predict possible failure scenarios. It will then provide estimates of typical PWHT cost eliminated by the current rules. It will provide an EPC contractor’s perspective on the current ASME B31 rules with practical approaches that may be taken to mitigate the risks. Finally, recommendations to the ASME B31 committees involved in PWHT exemption will be provided.

Effect of Postweld Heat Treatment on the Mechanical Properties of Weld in a Medium Carbon Steel

2013 ◽  
Vol 315 ◽  
pp. 6-10 ◽  
Author(s):  
S.M. Manladan ◽  
B.O. Onyekpe
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Steel ◽  
Postweld Heat Treatment ◽  
Medium Carbon Steel ◽  
Air Cooling ◽  
Shielded Metal Arc Welding ◽  
Medium Carbon ◽  
Before And After ◽  
Postweld Heat

This paper presents the result of an investigation of the effect of postweld heat treatment on the mechanical properties of weld in 0.36%C medium Carbon Steel. Samples were prepared and welded using Shielded Metal Arc Welding (SMAW) process with a low hydrogen electrode. The welded samples were subjected to postweld heat treatment (stress relief) at four different temperatures: 550°C, 600°C, 650°C and 700°C followed by air-cooling. Microstructural examination was carried out to determine the change in microstructure before and after postweld heat treatment. The mechanical properties of the samples were also tested before and after the heat treatment. It was established that a hard microstructure, susceptible to Hydrogen Induced Cracking (HIC), was formed in the heat affected zone of the as-welded samples and that postweld heat treatment improved the mechanical properties of the weld and substantially reduced or eliminated the risk of HIC.

Corrosion of Carbon Steel and Low-Alloy Steel Weldments

2006 ◽  
pp. 13-41
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Postweld Heat Treatment ◽  
Low Alloy Steels ◽  
Remedial Measures ◽  
Low Alloy Steel ◽  
Environmentally Assisted Cracking ◽  
Alloy Steels ◽  
Postweld Heat

Abstract Carbon and low-alloy steels are the most frequently welded metallic materials, and much of the welding metallurgy research has focused on this class of materials. Key metallurgical factors of interest include an understanding of the solidification of welds, microstructure of the weld and heat-affected zone (HAZ), solid-state phase transformations during welding, control of toughness in the HAZ, the effects of preheating and postweld heat treatment, and weld discontinuities. This chapter provides information on the classification of steels and the welding characteristics of each class. It describes the issues related to corrosion of carbon steel weldments and remedial measures that have proven successful in specific cases. The major forms of environmentally assisted cracking affecting weldment corrosion are covered. The chapter concludes with a discussion of the effects of welding practice on weldment corrosion.

scholarly journals Examining Stress Relaxation in a Dissimilar Metal Weld Subjected to Postweld Heat Treatment

2018 ◽  
Vol 7 (4) ◽  
pp. 20180018
Author(s):  
K. Abburi Venkata ◽  
S. Khayatzadeh ◽  
A. Achouri ◽  
J. Araujo de Oliveira ◽  
A. N. Forsey ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stress Relaxation ◽  
Postweld Heat Treatment ◽  
Dissimilar Metal ◽  
Dissimilar Metal Weld ◽  
Postweld Heat ◽  
Metal Weld

A Method for Applying Automatic Temperature Control to the Transient Finite Element Analysis of a Pressure Vessel Undergoing Postweld Heat Treatment

2004 ◽  
Author(s):  
Michael Sciascia
Keyword(s):  
Heat Treatment ◽  
Finite Element ◽  
Boundary Conditions ◽  
Temperature Profile ◽  
Pressure Vessel ◽  
Postweld Heat Treatment ◽  
Transient Temperature ◽  
Element Analysis ◽  
Heater Power ◽  
Postweld Heat

For complex finite element problems it is often desirable to prescribe boundary conditions that are difficult to quantify. The analysis of a pressure vessel undergoing postweld heat treatment (PWHT) is an example of such a problem. The PWHT process is governed by Code rules, but the temperature and gradient requirements they impose are not sufficient to precisely describe the complete vessel temperature profile. The imposition of such a profile in the analysis results in uncertainty and errors. A suitable but difficult approach is to specify heater power instead of temperatures, letting the solver determine the temperature profile. Unfortunately, the individual heater power levels necessary to meet the Code requirements are usually not known in advance. Determining the power levels necessary is particularly difficult if a transient solution is required. A means of actively controlling the heaters during the FEA solution is requirement for this approach. A simple and adaptive control algorithm was incorporated into the FEA solver via its scripting capability. Heat flux boundary conditions (heater power) were applied instead of transient temperature boundary conditions. Heater power levels were optimized to achieve predetermined time/temperature goals as the solution proceeded. The algorithm described was successfully applied to a pressure vessel PWHT with 14 zones of control. The approach may be adapted to other problems and boundary conditions.

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