Effects of laser heat treatment on salt spray corrosion of 1Cr5Mo heat resistant steel welding joints

2015 ◽  
Vol 22 (10) ◽  
pp. 3722-3730
Author(s):  
De-jun Kong ◽  
Wei Guo
Keyword(s):  
Heat Treatment ◽  
Salt Spray ◽  
Laser Heat Treatment ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Salt Spray Corrosion ◽  
Heat Resistant ◽  
Laser Heat ◽  
Welding Joints

Effect of Ausforming on Creep Strength of G91 Heat-Resistant Steel

2018 ◽  
Vol 941 ◽  
pp. 400-406 ◽  
Author(s):  
Javier Vivas ◽  
Rosalia Rementeria ◽  
Marta Serrano ◽  
Eberhard Altstadt ◽  
David San Martín ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Creep Strength ◽  
Operating Temperature ◽  
Strengthening Mechanism ◽  
Processing Route ◽  
Resistant Steel ◽  
Creep Tests ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Conventional Heat Treatment

The major challenge in a heat-resistant steel is to generate thermally stable microstructures that allow increasing the operating temperature, which will improve the thermal efficiency of the power plant without diminishing strength or time to rupture. The strengthening mechanism in tempered martensitic 9Cr steels comes mainly from the combination of solid solution effect and of precipitation hardening by fine MX carbo-nitrides, which enhance the sub-boundary hardening. This work is focused on the effect of ausforming processing on MX nanoprecipitation, on both their distribution and number density, during the subsequent tempering heat treatment. The creep strength at 700 oC was evaluated by small punch creep tests. The creep results after ausforming were compared to those obtained after conventional heat treatment concluding, in general, that ausforming boosts the creep strength of the steel at 700 oC. Therefore, conventional ausforming thermomechanical treatment is a promising processing route to raise the operating temperature of 9Cr heat-resistant steels.

Laser Assisted Cutting of Abrasion Resistant Steel

2012 ◽  
Vol 504-506 ◽  
pp. 1371-1376 ◽  
Author(s):  
Jani Kantola ◽  
Kari Mäntyjärvi ◽  
Jussi A. Karjalainen
Keyword(s):  
Heat Treatment ◽  
High Hardness ◽  
Strength Properties ◽  
Heat Treatments ◽  
Relative Depth ◽  
Laser Heat Treatment ◽  
Resistant Steel ◽  
Shearing Force ◽  
Laser Milling ◽  
Laser Heat

Abrasion resistant (AR) steels offer excellent hardness and strength properties in applications as mining and earth moving machines. As an outcome of high hardness AR steels can be used to produce durable, light-weight and energy saving products. However, their mechanical processing can be challenging as the hardness of the material approaches the hardness of the tooling used. This places high forces on cutting tools and machines, which, in turn, increases wear and causes early breakdown. This research examines whether the laser treatment of AR steels can be used to aid guillotine shearing. The tested material was abrasion resistant steel with hardness of 400 HBW. Two different laser treatments were examined: local laser heat treatment and laser milling. The aim of laser heat treatment was to change the original martensitic microstructure locally into weaker structure, beneficially for shearing. Narrow grooves were made along the cut line by laser milling, and then the plate cut along them. The effect of local laser heat treatment and the fracture initiating effect of the groove was evaluated from the cutting force. Microhardness tests and micro photos were taken after laser heat treatments. The results indicated that the shearing force of AR steels can be reduced up to 25% with the aid of laser heat treatments. Laser milling had only a slight effect to the shearing force of up to about 8%. In addition, the relative depth of the laser milled groove is estimated at the same range, thus force reduction is mainly due to reduction of material thickness.

scholarly journals Precipitate Evolution in 22Cr25NiWCuCo(Nb) Austenitic Heat-Resistant Stainless Steel during Heat Treatment at 1200 °C

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1104
Author(s):  
Sheng-Min Yang ◽  
Jing-Lin Wu ◽  
Yeong-Tsuen Pan ◽  
Dong-Yih Lin
Keyword(s):  
Heat Treatment ◽  
Volume Fraction ◽  
Steel Matrix ◽  
Resistant Steel ◽  
Precipitation Behavior ◽  
Scanning Calorimetry ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Nb Content ◽  
Austenitic Grain Size

In this study, 22Cr25NiWCuCo(Nb) heat-resistant steel specimens with high Cr and Ni contents were adopted to investigate the effect of Nb content on thermal and precipitation behavior. Differential scanning calorimetry profiles revealed that the melting point of the 22Cr25NiWCuCo(Nb) steel specimens decreased slightly with the Nb content. After heat treatment at 1200 °C for 2 h, the precipitates dissolved in a Nb-free steel matrix. In addition, the Z phase (CrNb(C, N)) and MX (Nb(C, N), (Cr, Fe)(C, N), and NbC) could be observed in the Nb-containing steel specimens. The amount and volume fraction of the precipitates increased with the Nb content, and the precipitates were distributed heterogeneously along the grain boundary and inside the grain. Even when the heat treatment duration was extended to 6 h, the austenitic grain size and precipitates became coarser; the volume fraction of the precipitates also increased at 1200 °C. The Z phase, rather than the MX phase, became the dominant precipitates at this temperature.

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.

Sign in / Sign up

Export Citation Format

Share Document