Strength increase in the coarse-grained heat-affected zone of a high-strength, blast-resistant steel after post-weld heat treatment

2013 ◽  
Vol 585 ◽  
pp. 149-154 ◽  
Author(s):  
Xin Yue ◽  
Xiuli Feng ◽  
John C. Lippold
Keyword(s):  
Heat Treatment ◽  
Heat Affected Zone ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Coarse Grained ◽  
Strength Increase ◽  
Resistant Steel ◽  
Weld Heat

scholarly journals Metallurgical Effects of Niobium and Molybdenum on Heat-Affected Zone Toughness in Low-Carbon Steel

2019 ◽  
Vol 9 (9) ◽  
pp. 1847 ◽  
Author(s):  
Hardy Mohrbacher
Keyword(s):  
Heat Treatment ◽  
Heat Affected Zone ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Coarse Grained ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Structural Applications ◽  
Steel Grades ◽  
Weld Heat

Modern weldable high strength steel grades are typically based on low-carbon alloy concepts using microalloying for obtaining a good strength-toughness balance. Such steel grades having a yield strength in the range of 420 to 690 MPa are very commonly used in pipelines, heavy vehicles, shipbuilding and general structural applications. Thermomechanical processing during hot rolling combined with accelerated cooling is an established means of producing such steel grades. Considering the alloying concepts, the use of niobium and molybdenum, and in selected cases boron, is very efficient to achieve high strength and good toughness. However, all targeted applications of such high strength steels involve extensive welding. Thus, heat affected zone properties are of particular importance. The present paper investigates the effects of Nb, Mo and Ti on the heat affected zone properties. Variations of the Mn and Si contents are considered as well. Additionally, the influence of post-weld heat treatment in the coarse-grained heat-affected zone (HAZ) is considered. In this approach, HAZ subzones were generated using laboratory weld cycle simulations in combination with systematic variation of alloying elements to scrutinize and interpret their specific effects. The results indicate that Mo and Nb, when alloyed in the typical range, provide excellent HAZ toughness and guarantee sufficiently low ductile-to-brittle transition temperature. An alloy combination of Nb, Mo and Ti improves performance under hot deformation conditions and toughness after post-weld heat treatment.

Effect of Post-Weld Heat Treatment on Carbide Precipitation and Impact Properties of Coarse-Grained Heat-Affected Zone of Q690 Steel

2014 ◽  
Vol 989-994 ◽  
pp. 576-580 ◽  
Author(s):  
Zhen Shun Li ◽  
Sheng Li Li ◽  
Lei Tian ◽  
Xiang Hai Zhang ◽  
Ji Zhi Liu
Keyword(s):  
Heat Treatment ◽  
Grain Boundaries ◽  
Heat Affected Zone ◽  
Unit Area ◽  
Carbide Precipitation ◽  
Post Weld Heat Treatment ◽  
Coarse Grained ◽  
Impact Properties ◽  
Carbide Particles ◽  
Weld Heat

The effect of post-weld heat treatment (PWHT) on carbide precipitation and impact properties of coarse-grained heat-affected zone (CGHAZ) of Q690 Steel was studied in this paper. Carbide particles precipitated primarily at prior austenite grain boundaries and martensitic lath boundaries. When the PWHT temperature is 520–570 °C, temper embrittlement occurs. This temperature range is also where the number of carbide particles per unit area at grain boundaries reaches its maximum. The high number of particles per unit area increases the rate of crack initiation at grain boundaries under rapid loading; linking of microcracks along grain boundaries which are already weakened by impurity segregation results in TE and intergranular fracture.

The Effect of PWHT on the Material Properties and Micro Structure in Inconel 625 and Inconel 725 Buttered Joints

2003 ◽  
Author(s):  
Vigdis Olden ◽  
Per Egil Kvaale ◽  
Per Arne Simensen ◽  
Synno̸ve Aaldstedt ◽  
Jan Ketil Solberg
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Post Weld Heat Treatment ◽  
Fusion Line ◽  
Coarse Grained ◽  
Inconel 625 ◽  
Micro Structure ◽  
Mixed Zone ◽  
Heat Treated ◽  
Weld Heat

This report describes investigations performed on as welded and post weld heat treated samples of AISI 8630 steel, buttered with Inconel 625 and Inconel 725. The investigations have focused on the properties and microstructure in the partial mixed zone between the buttering and the steel before and after post weld heat treatment. The samples were heat treated for 4 1/2 hours at 640°C, 665° and 690°C and investigated with respect to mechanical properties and microstructure near the fusion line. A range of testing and analyses were performed including notch impact toughness testing, identification of fracture initiation and propagation in impact specimens, hydrogen measurements, examination of the micro structure in steel and Inconel using light microscope, hardness testing and electron micro-probe analysis of the alloying elements across the fusion line. Additional investigations in TEM on samples from an actual joint, post weld heat treated at 665°C were also performed. The results show that post weld heat treatment at 665°C and 690°C reduced the impact toughness in coarse grained heat affected zone, caused by decarburisation, ferrite formation and grain growth. The partially mixed zone (5–10μm) of the Inconel buttering, gained partly extremely high hardness caused by carbon enrichment, reaustenitization and formation of virgin martensite. As welded samples gave more favorable properties and microstructure than the post weld heat treated ones.

Fatigue of Laserbeam Welded Joints of High-Carbon Steel Strips

2010 ◽  
Vol 659 ◽  
pp. 61-66
Author(s):  
Attila Magasdi ◽  
János Ginsztler ◽  
János Dobránszky
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Steel ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
High Carbon Steel ◽  
Post Weld Heat Treatment ◽  
High Carbon ◽  
Steel Strips ◽  
Weld Heat

The high-carbon steel strips are one of the most widely used base materials of bandsaw blade manufacturing. These materials have sufficient strength and ductility to cope with the high fatigue load of the bandsaw blades. These endless strips are produced by welding, and therefore the weld and the heat affected zone have different mechanical properties, like tensile strength and fatigue resistance, than the base material. These properties of the weld can be influenced by preheat and post weld heat treatment. Regarding to the latest industrial requirements, the application of laserbeam welding was examined to produce higher standard bandsaw blade. The laserbeam welded joints has lower heat input and narrower heat affected zone compared to metal inert gas (MIG) welding, which is currently used in bandsaw blade manufacturing. To assure the proper mechanical properties and sufficient resistance to fatigue, an examination was carried out to determine the effect of preheat temperature and post weld heat treatment time on the mechanical properties and fatigue behaviour of the laserbeam welded joint.

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