High Heat Input Welding of 12Cr-6Ni-2.5Mo Supermartensitic Stainless Steel

Author(s):  
Ragnhild Aune ◽  
Hans Fostervoll ◽  
Odd Magne Akselsen

In conventional welding of 13% Cr supermartensitic stainless steels, the normal microstructure that forms on cooling is martensite. Although high heat input tends to give a certain coarsening of the final microstructure, the eventual accompanying loss in toughness is not known. The present study was initiated to examine the effect of heat input on weld metal and heat affected zone mechanical properties of a 12Cr-6Ni-2.5Mo grade. The results obtained showed that the notch toughness is low (25 J) and independent of heat input for the weld metal, while it is reduced with increasing heat input for fusion line and the heat affected zone locations. Subsequent post weld heat treatment gave a substantial increase in toughness for all notch locations. Based on these results, indications are that a specified maximum heat input is not applicable in welding of supermartensitic stainless steels, allowing more production efficient techniques to be used, both in longitudinal seam and girth welding.

2018 ◽  
Vol 115 (4) ◽  
pp. 410
Author(s):  
Fengyu Song ◽  
Yanmei Li ◽  
Ping Wang ◽  
Fuxian Zhu

Three weld metals with different oxygen contents were developed. The influence of oxygen contents on the microstructure and impact toughness of weld metal was investigated through high heat input welding tests. The results showed that a large number of fine inclusions were formed and distributed randomly in the weld metal with oxygen content of 500 ppm under the heat input condition of 341 kJ/cm. Substantial cross interlocked acicular ferritic grains were induced to generate in the vicinity of the inclusions, primarily leading to the high impact toughness at low temperature for the weld metal. With the increase of oxygen content, the number of fine inclusions distributed in the weld metal increased and the grain size of intragranular acicular ferrites decreased, which enhanced the impact toughness of the weld metal. Nevertheless, a further increase of oxygen content would contribute to a great diminution of the austenitic grain size. Following that the fraction of grain boundary and the start temperature of transformation increased, which facilitated the abundant formation of pro-eutectoid ferrites and resulted in a deteriorative impact toughness of the weld metal.


2015 ◽  
Vol 55 (9) ◽  
pp. 2018-2026 ◽  
Author(s):  
Takako Yamashita ◽  
Junji Shimamura ◽  
Kenji Oi ◽  
Masayasu Nagoshi ◽  
Katsunari Oikawa ◽  
...  

2016 ◽  
Vol 47 (7) ◽  
pp. 3354-3364 ◽  
Author(s):  
Long-Yun Xu ◽  
Jian Yang ◽  
Rui-Zhi Wang ◽  
Yu-Nan Wang ◽  
Wan-Lin Wang

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