热处理气氛对 2205 双相不锈钢焊接件组织演变和耐腐蚀性的影响。

Effect of heat treatment atmospheres on microstructure evolution and corrosion resistance of 2205 duplex stainless steel weldments.

机构信息

Mechanical Production Department, Faculty of Technology & Education, Suez University, Suez, 43527, Egypt.

Central Metallurgical Research and Development Institute (CMRDI), Cairo, Egypt.

出版信息

Sci Rep. 2023 Mar 21;13(1):4592. doi: 10.1038/s41598-023-31803-5.

DOI:10.1038/s41598-023-31803-5

PMID:36944794

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10030882/

Abstract

The effects of post heat treatment atmosphere on microstructure and corrosion resistance of duplex stainless steel welded joints were investigated. Post weld heat treatment (PWHT) was carried out with and without protective atmospheres. Nitrogen and argon are used as protective gases individually. Detailed microstructure examination (optical and SEM) demonstrates that nitrides precipitates are highly observed in the welded zones for nitrogen protected samples. An observed drop of ferrite volume fraction in post weld heat treated samples compared with welded samples without heat treatment leading to corrosion resistance enhancement of heat treated welded joints. An exception for using nitrogen as heat treatment atmosphere a decreased corrosion resistance of weldments is investigated due to nitride precipitates. An increase in the weld zone hardness for post weld heat treated samples compared with base alloy. The initial hardness of duplex stainless steel was 286 Hv while average hardness of weld zone was 340, 411, 343, and 391 Hv for as welded, PWHT using air, argon, and nitrogen atmospheres, respectively. Weld zone hardness increased to 33, 44, 20, and 37%. A significant decrease in the ultimate tensile strength and elongation after PWHT. The initial Ultimate tensile strength duplex stainless steel base material was 734.9 MPa while Ultimate tensile strength of the welded joints was 769.3, 628.4, 737.8, and 681.4 MPa for the following conditions: as welded, PWHT using air, argon, and nitrogen atmospheres, respectively.

摘要

研究了焊后热处理气氛对双相不锈钢焊接接头组织和耐腐蚀性的影响。进行了有和没有保护气氛的焊后热处理（PWHT）。分别使用氮气和氩气作为保护气体。详细的微观结构检查（光学和 SEM）表明，在氮气保护的样品焊接区中观察到大量的氮化物沉淀。与未经热处理的焊接样品相比，焊后热处理样品中的铁素体体积分数下降，导致热处理焊接接头的耐腐蚀性增强。由于氮化物沉淀，在使用氮气作为热处理气氛时，焊接件的耐腐蚀性会下降，这是一个例外。与母材相比，焊后热处理样品的焊接区硬度增加。双相不锈钢的初始硬度为 286Hv，而焊接区的平均硬度分别为 340、411、343 和 391Hv，对于未经处理、使用空气、氩气和氮气气氛进行 PWHT 的情况。焊接区硬度增加了 33、44、20 和 37%。PWHT 后，极限拉伸强度和伸长率显著下降。双相不锈钢母材的初始极限拉伸强度为 734.9MPa，而在以下条件下焊接接头的极限拉伸强度分别为 769.3、628.4、737.8 和 681.4MPa：未经处理、使用空气、氩气和氮气气氛进行 PWHT。