scholarly journals Effect of PWHT Temperature and Time on Hardness and Microstructure of 410NiMo Weld Metal

2018 ◽  
Author(s):  
Uğur Özdemir ◽  
Selçuk Keskinkılıç ◽  
Filiz K. Acar ◽  
Fikret Kabakci ◽  
Mustafa Acarer
Keyword(s):  
Heat Treatment ◽  
Weld Metal ◽  
Hydraulic Turbine ◽  
Post Weld Heat Treatment ◽  
Fatigue Properties ◽  
Shielded Metal Arc Welding ◽  
Weld Metals ◽  
Metal Arc Welding ◽  
Hardness Tests ◽  
Weld Heat

ASTM A743 CA6NM alloy is a martensitic stainless steel typically used in energy industry -runners and hydraulic turbine components- due to its superior toughness, yield and fatigue properties. In both the manufacturing, shielded metal arc welding is applied to join for this grade steels. However, weldability of the steels is limited due to formation of hard and brittle phases such as untempered martensite during welding and post weld heat treatment processes. The formation causes a reduction in toughness. In this study, influence of post-weld heat treatment procedure (single tempering and double tempering) and parameters on microstructure and hardness of AWS410NiMo all weld metal. Hardness tests were conducted from weld metal. Microstructures of the all weld metals subjected to different heat treatment process were characterized.

scholarly journals Pengaruh Post Weld Heat Treatment (Pwht) dengan Pemanas Induksi Terhadap Sifat Mekanik dan Struktur Mikro Sambungan Las Shield Metal Arc Welding (Smaw) pada Pipa API 5l X52

ROTASI ◽  
2017 ◽  
Vol 19 (3) ◽  
pp. 117 ◽  
Author(s):  
Gunawan Dwi Haryadi ◽  
Rifky Ismail ◽  
Mahmuda Haira
Keyword(s):  
Heat Treatment ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Arc Welding ◽  
Post Weld Heat Treatment ◽  
Holding Time ◽  
Metal Arc Welding ◽  
Weld Heat

Saluran perpipaan telah digunakan sebagai salah satu metode yang paling praktis dan  berharga murah untuk transportasi minyak dan gas. Penyambungan pipa sendiri dilakukan dengan proses pengelasan. Pada pengelasan memunculkan efek pemanasan setempat dengan temperatur tinggi yang menyebabkan logam mengalami ekspansi termal maupun penyusutan saat pendinginan. Hal itu menyebabkan terjadinya tegangan sisa, perubahan struktur mikro, kekerasan dan ketangguhan yang berbeda-beda pada tiap-tiap daerah konstruksi. Salah satu cara untuk memperbaiki hal tersebut yaitu dengan cara melakukan post weld heat treatment (PWHT). Penelitian ini bertujuan untuk mengetahui pengaruh PWHT terhadap sifat mekanik dan struktur mikro pada pengelasan shield metal arc welding (SMAW). PWHT dilakukan dengan menggunakan alat pemanas induksi pada temperatur 400ºC, 500 ºC 600 ºC, 700 ºC dan 800 ºC dengan holding time selama 15 detik dan didinginkan di udara terbuka. Selanjutnya dilakukan pengujian impak, kekerasan dan struktur mikro untuk mengetahui pengaruh PWHT yang dilakukan. Dari hasil pengujian impak dan kekerarasan diketahui bahwa semakin tinggi temperature PWHT maka semakin tinggi juga nilai ketangguhan dan semakin menurun nilai kekerasannya. Dan dari pengamatan struktur mikro daerah weld metal PWHT mengakibatkan terjadinya peningkatan jumlah struktur acicular ferrite dan penurunan jumlah struktur widmanstatten ferrite.

The Formation and Control of Laves Phase in K418 and 42CrMo Dissimilar Metal Laser Weld

2012 ◽  
Vol 166-169 ◽  
pp. 1839-1842 ◽  
Author(s):  
Ming Pang ◽  
Chang Zhen Liu ◽  
Guang Hui Xu ◽  
Jun Hua Ma
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Post Weld Heat Treatment ◽  
Laves Phase ◽  
Laser Weld ◽  
Dissimilar Metal ◽  
Weld Metals ◽  
Transmission Electron ◽  
And Control ◽  
Weld Heat

The effect of K418 and 42CrMo dissimilar metal laser welding velocity, temperature of post-weld heat treatment on controlling formation of laves phase were investigated. Microstructure and laves phase were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).Results showed that Laves phase formed in the interdendritic regions of the weld metals as a result of segregation. The morphology and composition of Laves phase depended strongly on heat input/cooling rate and influenced its response to subsequent homogenization post-weld heat treatment.

The Characteristics of Weld Metal Zone Welded with Various Filler Metals

2013 ◽  
Vol 690-693 ◽  
pp. 2673-2677
Author(s):  
Kyung Man Moon ◽  
Mun Jin Nam ◽  
Yeon Chang Lee ◽  
Yun Hae Kim ◽  
Jae Hyun Jeong
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Weld Metal ◽  
Post Weld Heat Treatment ◽  
Fuel Oil ◽  
Corrosion Properties ◽  
Repair Welding ◽  
Piston Crown ◽  
Filler Metals ◽  
Weld Heat

Recently, the fuel oil of diesel engines of marine ships is being changed to heavy oil of low quality as the oil price is getting higher and higher. Therefore, the wear and corrosion in all parts of the engine, such as cylinder liner, piston crown, and spindle and seat ring of exhaust valves has predominantly increased. Thus, the repair welding of the piston crown is a unique method to prolong its life in a economical point of view. In this case, filler metals with a high corrosion and wear resistance are mainly being used for repair welding. However, the piston crown on the ships job site is often actually being welded with mild filler metals. Therefore, in this study, mild filler metals, such as E4301, E431316, and E4316, were welded to the SS401 steel as the base metal, and the corrosion properties of their weld metals with and without post weld heat treatment were investigated with some electrochemical methods in 0.1% H2SO4 solution. The weld metal welded with E4301 filler metal exhibited the best corrosion resistance among the filler metals in the case of no heat treatment, however, its resistance was considerably decreased due to the post weld heat treatment (annealing:625°C, 2hr). In particular, the weld metal of E4316 exhibited relatively a good corrosion resistance by the post weld heat treatment.

Post-weld heat treatment cracking susceptibility of T23 weld metals for fossil fuel applications

2012 ◽  
Vol 34 ◽  
pp. 699-706 ◽  
Author(s):  
Kiduck Park ◽  
Sanghoon Kim ◽  
Jungchel Chang ◽  
Changhee Lee
Keyword(s):  
Heat Treatment ◽  
Fossil Fuel ◽  
Post Weld Heat Treatment ◽  
Weld Metals ◽  
Weld Heat

Effect of the FCAW Welding Process and Post Weld Heat Treatment on the Properties and Microstructure of the Weld Joints of Heat Treated 4330V Steel

2015 ◽  
Vol 809-810 ◽  
pp. 437-442
Author(s):  
Jacek Górka ◽  
Michał Miłoszewski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Metal ◽  
Heat Input ◽  
Large Diameter ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
High Toughness ◽  
Interpass Temperature ◽  
Weld Heat

4330V is a high strength, high toughness, heat treatable low alloy steel for application in the oil, gas and aerospace industries. It is typically used for large diameter drilling parts where high toughness and strength are required. The research describes the effect of preheat temperature, interpass temperature, heat input, and post weld heat treatment on strength, hardness, toughness, and changes to microstructure in the weld joint. Welding with the lower heat input and no post weld heat treatment resulted in optimal mechanical properties in the weld metal. Austempering at 400 °C resulted in optimal mechanical properties in the HAZ. Increasing preheat and interpass temperature from 340 °C to 420 °C did not improve Charpy V-notch values or ultimate tensile strength in the weld metal or heat affected zones. The higher temperature increased the width of the heat affected zone. Austempering at 400 °C reduced HAZ hardness to a level comparable to the base metal. Both tempering and austempering at 400 °C for 10 hours reduced toughness in the weld metal.

Weld Hardness Study of P91 Welded Pipes with Post Weld Heat Treatment for Elevated Temperature Application in Power Plants

2015 ◽  
Vol 1115 ◽  
pp. 503-508 ◽  
Author(s):  
Muhammad Sarwar ◽  
Mohd Amin bin Abd Majid
Keyword(s):  
Heat Treatment ◽  
Power Plant ◽  
Weld Metal ◽  
Creep Strength ◽  
Power Plants ◽  
Thermal Power ◽  
Base Material ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Weld Heat

The creep strength-enhanced ferritic (CSEF) steels are undergoing an encouraged use around the world especially in power plant construction. On construction sites, it has always been the target to have no problems in welded joints but premature failures are being encountered. The primary reason of these premature failures is found to be the improper heat treatment that is mandatorily carried out to achieve the required weld hardness. Weld hardness has close relationship with creep strength and ductility of the welded structures. Hence it is important for any weld to achieve certain level of weld hardness. This study aims at ascertaining the importance of Post Welding Heat Treatment (PWHT) in achieving the required hardness in creep-strength enhanced ferritic (CSEF) materials.The study was carried out on the welding of alloy steel ASTM A335 Gr. P-91 with the same base material (ASTM A335 Gr. P-91) by Gas Tungsten Arc Welding (GTAW) process using ER90S-B9 filler wire with pre-heat of 200oC (min) and inter-pass temperature of 300oC (max). After welding, the joints were tested for soundness with Radiography testing. Induction heating was used for heat treatment of P91 pipes during welding and post weld heat treatment. The effect of Post Weld Heat Treatment (PWHT) was investigated on the Weld metal and the Heat Affected Zones (HAZ) by hardness testing. It is perceived that the scattered and higher hardness values, more than 250HB in 2” P91 pipes in the weld metal and in the heat affected zones, can be brought into the lower required level, less than 250HB, with an effective post weld heat treatment at 760°C for 2hrs.It is concluded that PWHT is the most effective way of relieving the welding stresses that are produced due to high heat input in the welding process and to achieve the required level of hardness in the weld as well as in the heat affected zones (HAZ) in thermal power plant main steam piping.

Effect of Post Weld Heat Treatment on Weld Hardness Quality of P91 Welded Pipes

2015 ◽  
Vol 799-800 ◽  
pp. 377-381
Author(s):  
Mohd Amin Abd Majid ◽  
Muhammad Sarwar
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welded Joint ◽  
Post Weld Heat Treatment ◽  
Bead Geometry ◽  
Construction Sites ◽  
Weld Heat

Quality of a weld produced is generally evaluated by different parameters such as weld size, bead geometry, deposition rate, hardness and strength. A common problem that has been faced at the construction sites is to obtain a good welded joint having the required strength with minimal detrimental residual stresses to avoid any premature cracking due to high variation of hardness. In order to address this issue and to attain good weld quality, this study has been made to comprehend the effect of the post weld heat treatment on P91 material welds produced by TIG welding. Findings from the studies indicate that the PWHT has significant influence on the weld hardness of Alloy Steel-A335 P91 pipes. It is eminent that during cooling, after welding of P91, quenched martensite was formed in the HAZ that results in an increased hardness to an undesirable level of more than 250HB. PWHT at temperature of 760°C for 2 hours has good influence on mechanical properties as the hardness decreases and turns out to be uniformly distributed. If the PWHT is correctly carried out, the hardness of parent metals, heat affected zones and weld metal can be brought into the required limits to avoid any premature cracking due to high variation of hardness.

scholarly journals The Influence of Post-Weld Heat Treatment on the Microstructure and Fatigue Properties of Sc-Modified AA2519 Friction Stir-Welded Joint

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 583 ◽  
Author(s):  
Robert Kosturek ◽  
Lucjan Śnieżek ◽  
Marcin Wachowski ◽  
Janusz Torzewski
Keyword(s):  
Heat Treatment ◽  
Precipitation Hardening ◽  
Low Cycle Fatigue ◽  
True Strain ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Fatigue Properties ◽  
Friction Stir ◽  
Scanning Electron ◽  
Weld Heat

The aim of this research was to investigate the influence of post-weld heat treatment (PWHT, precipitation hardening) on the microstructure and fatigue properties of an AA2519 joint obtained in a friction stir-welding process. The welding process was performed with three sets of parameters. One part of the obtained joints was investigated in the as-welded state and the second part of joints was subjected to the post-weld heat treatment (precipitation hardening) and then investigated. In order to establish the influence of the heat treatment on the microstructure of obtained joints both light and scanning electron microscopy observations were performed. Additionally, microhardness analysis for each sample was carried out. Fatigue properties of the samples in the as-welded state and the samples after post-weld heat treatment were established in a low-cycle fatigue test with constant true strain amplitude equal to ε = 0.25% and cycle asymmetry coefficient R = 0.1. Hysteresis loops together with changes of stress and plastic strain versus number of cycles are presented in this paper. The fatigue fracture in tested samples was analyzed with the use of scanning electron microscope. Our results show that post-weld heat treatment of AA2519 friction stir-welded joints significantly decreases their fatigue life.

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