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.

Post-weld Heat Treatment and Groove Angles Affect the Mechanical Properties of T92/Super 304H Dissimilar Steel Weld Joints

2018 ◽  
Vol 37 (7) ◽  
pp. 649-654 ◽  
Author(s):  
Wang Shuo ◽  
Wei Limin ◽  
Cheng Yi ◽  
Tan Shuping
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Metal ◽  
Arc Welding ◽  
Post Weld Heat Treatment ◽  
Steel Weld ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
Gas Tungsten Arc ◽  
Weld Heat

AbstractThe microstructures and mechanical properties of dissimilar weld joints between T92 and Super 304H steels were investigated. Dissimilar weld joints with four groove angles were constructed using gas tungsten arc welding. The results showed that post-weld heat treatment improved the mechanical properties of the dissimilar weld joints. The optimal groove angle for T92/Super 304H dissimilar weld joints was found to be 20°, considering mechanical properties. Furthermore, the transformation from equiaxed dendrites to columnar dendrites was observed in the weld metal. Epitaxial growth and delta ferrites were found around the fusion line between the Super 304H and the weld metal.

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 Waktu Penahanan pada Perlakuan Panas Paska Pengelasan terhadap Ketangguhan Sambungan Las Baja

2019 ◽  
Vol 13 (2) ◽  
pp. 80
Author(s):  
Muhamad Fitri ◽  
Bambang Sukiyono ◽  
Martua Limido Simanjuntak
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Local Heating ◽  
Post Weld Heat Treatment ◽  
Impact Testing ◽  
Holding Time ◽  
Aisi 4130 ◽  
The Impact ◽  
Holding Temperature ◽  
Weld Heat

One of the welding methods that is widely used today because it is easier to operate, more practical in its use, can be used for all welding positions and more efficient is called Shield Metal Arc Welding (SMAW). In this welding, the base metal and filler metal will experience thermal cycles which lead to local heating and cooling processes resulting in residual stress and distortion in the material. This residual stress must be removed because it causes a decrease in the mechanical properties of the material. The most widely used method is the thermal method that is by Post Weld Heat Treatment (PWHT). The success of The post-weld heat treatment in removing residual stresses in PWHT is influenced by the holding time. This study aims to examine the effect of holding time on heat treatment, on the weld toughness of steel. In this study, the type of welding used was SMAW welding, the material used was steel AISI 4130, the electrodes used were LB-7018-1 standard application and AWS classification A5.1 E7018-1. The test holding temperature is 650oC. The holding time of testing uses three variables, namely: 2.5 hours, 4.5 hours, 6.5 hours. The Impact testing is done by the Charpy method. From this study, the influence of holding time variation on PWHT holding temperature on the weld strength of AISI 4130 steel was obtained.

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.

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.

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