Effect of Heat Input on Microstructure and Hardness of SKD 61 Hot Work Tool Steel Using Gas Metal Arc Welding

2012 ◽  
Vol 557-559 ◽  
pp. 1275-1280 ◽  
Author(s):  
Teerayut Kanchanasangtong ◽  
Supachai Surapunt

The purpose of this research is to study the effect of heat input on microstructure and hardness of SKD 61 hot work tool steel by using Gas Metal Arc Welding (GMAW) process. The specimens made of SKD 61 steel plates were austenized and oil-quenched to room temperature, then they were double tempered. Base on identical welding specification procedure (WPS), the specimens were automatically welded by GMAW machine. The consumable copper coated-solid wire electrode was used for surfacing in the GMAW process. The microstructures at the HAZ of specimens for all conditions were composed mainly of martensite with some retained austenite in the dendritic segregation pattern. With the higher heat input resulted in increasing in hardness, which resulted from transformation of retained austenite to martensite.

2013 ◽  
Vol 339 ◽  
pp. 700-705 ◽  
Author(s):  
Victor Lopez ◽  
Arturo Reyes ◽  
Patricia Zambrano

The effect of heat input on the transformation of retained austenite steels transformation induced plasticity (TRIP) was investigated in the heat affected zone (HAZ) of the Gas Metal Arc Welding GMAW process. The determination of retained austenite of the HAZ is important in optimizing the welding parameters when welding TRIP steels, because this will greatly influence the mechanical properties of the welding joint due to the transformation of residual austenite into martensite due to work hardening. Coupons were welded with high and low heat input for investigating the austenite transformation of the base metal due to heat applied by the welding process and was evaluated by optical microscopy and the method of X-Ray Diffraction (XRD). Data analyzed shows that the volume fraction of retained austenite in the HAZ increases with the heat input applied by the welding process, being greater as the heat input increase and decrease the cooling rate, this due to variation in the travel speed of the weld path.


Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5666
Author(s):  
Miloš Mičian ◽  
Jerzy Winczek ◽  
Marek Gucwa ◽  
Radoslav Koňár ◽  
Miloslav Málek ◽  
...  

In this paper, the experimental investigation results of the bead sequence input on geometry, structure, and hardness of surfaced layers after multi-pass weld surfacing are analyzed. Three S355 steel plates surfaced by GMAW (Gas Metal Arc Welding) were tested with three different combinations of six beads. The geometric, structural, and hardness analysis was carried out in the cross-section of the plates in the middle of the welded layers. The dimensions of padded layers, fusion and heat-affected zone, as well as the individual padded weld were evaluated. On the basis of metallographic samples, qualitative and quantitative structure analysis was performed. Hardness measurements in surfacing welds and heat-affected zones in the tested cross-sections of the surfacing layers were carried out. A comparative analysis of structure and hardness, taking into account the thermal implications of the bead sequence, allowed for the formulation of conclusions. Comparative studies have shown differences in properties between heat-affected zones (HAZ) for individual surfacing sequences. These differences were mainly in the dimensions of the surfacing layers, the share of structural components, as well as the uniformity of hardness distributions. Finally, the most favorable sequence in terms of structure and hardness distribution, maximum hardness, and range of hardness has been indicated.


2016 ◽  
Vol 24 (05) ◽  
pp. 1750069
Author(s):  
T. PRABAKARAN ◽  
M. PRABHAKAR ◽  
P. SATHIYA

This paper deals with the effects of shielding gas mixtures (100% CO2, 100% Ar and 80 % Ar [Formula: see text] 20% CO[Formula: see text] and heat input (3.00, 3.65 and 4.33[Formula: see text]kJ/mm) on the mechanical and metallurgical characteristics of AISI 410[Formula: see text]S (American Iron and Steel Institute) super martensitic stainless steel (SMSS) by gas metal arc welding (GMAW) process. AISI 410[Formula: see text]S SMSS with 1.2[Formula: see text]mm diameter of a 410 filler wire was used in this study. A detailed microstructural analysis of the weld region as well as the mechanical properties (impact, microhardness and tensile tests at room temperature and 800[Formula: see text]C) was carried out. The tensile and impact fracture surfaces were further analyzed through scanning electron microscope (SEM). 100% Ar shielded welds have a higher amount of [Formula: see text] ferrite content and due to this fact the tensile strength of the joints is superior to the other two shielded welds.


10.30544/682 ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 505-517
Author(s):  
Ashok Kumar Srivastava ◽  
Pradip K Patra

With an increasing demand for safer and greener vehicles, mild steel and high strength steel are being replaced by much stronger advanced high strength steels of thinner gauges. However, the welding process of advanced high strength steels is not developed at the same pace. The performance of these welded automotive structural components depends largely on the external and internal quality of weldment. Gas metal arc welding (GMAW) is one of the most common methods used in the automotive industry to join car body parts of dissimilar high strength steels. It is also recognized for its versatility and speed. In this work, after a review of GMAW process and issues in welding of advanced high strength steels, a welding experiment is carried out with varying heat input by using spray and pulse-spray transfer GMAW method with filler wires of three different strength levels. The experiment results, including macro-microstructure, mechanical properties, and microhardness of weld samples, are investigated in detail. Very good weldability of S650MC is demonstrated through the weld joint efficiency > 90%; no crack in bending of weld joints, or fracture of tensile test sample within weld joint or heat affected zone (HAZ), or softening of the HAZ. Pulse spray is superior because of thinner HAZ width and finer microstructure on account of lower heat input. The impact of filler wire strength on weldability is insignificant. However, high strength filler wire (ER100SG) may be chosen as per standard welding practice of matching strength.


2013 ◽  
Vol 68 (9-12) ◽  
pp. 2833-2840 ◽  
Author(s):  
Luisa Quintino ◽  
Olga Liskevich ◽  
Louriel Vilarinho ◽  
Américo Scotti

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