Weld Repair of 2-1/4Cr-1Mo Service-Aged Header Welds

1999 ◽  
Vol 121 (4) ◽  
pp. 345-352 ◽  
Author(s):  
R. Viswanathan ◽  
D. Gandy ◽  
S. Findlan
Keyword(s):  
Heat Treatment ◽  
Arc Welding ◽  
Rupture Life ◽  
Postweld Heat Treatment ◽  
Creep Rupture ◽  
Shielded Metal Arc Welding ◽  
Weld Repair ◽  
Metal Arc Welding ◽  
Girth Welds ◽  
Postweld Heat

The objective of this investigation was to evaluate the efficacy of different weld repair techniques as applied to service-aged 2-1/4Cr-1Mo steel weldments. A header which had been in service for 244,000 h at 1050°F (565°C) was utilized for the study. Three girth welds were partially excavated and subjected to repairs using gas tungsten arc welding (GTAW), shielded metal arc welding (SMAW) with postweld heat treatment (PWHT), and without postweld heat treatment using a temperbead technique. Results show that all the weld repairs improved the creep rupture lives of the ex-service weldments and that remaining lives of several decades could be achieved in the repaired condition. The SMAW-temperbead repairs resulted in increase of rupture life, tensile strength, and impact toughness compared to the SMAW-PWHT repairs. The GTAW-PWHT repairs also produced a superior combination of mechanical properties. Remaining creep rupture lives were a function of the extrapolation procedure and specimen size. These results are described here and discussed in comparison with results previously reported for a less severely degraded condition of the steel in order to delineate the effect of prior degradation on weld repair performance.

Weld Repair of Aged Cr-Mo Steel Piping—A Review of Literature

1999 ◽  
Vol 122 (1) ◽  
pp. 76-85 ◽  
Author(s):  
R. Viswanathan ◽  
D. Gandy
Keyword(s):  
Arc Welding ◽  
Elevated Temperatures ◽  
Postweld Heat Treatment ◽  
Repair Process ◽  
Point Of View ◽  
Shielded Metal Arc Welding ◽  
Weld Repair ◽  
Promising Alternative ◽  
Metal Arc Welding ◽  
Study Results

Power plant piping operating at elevated temperatures is subject to several types of service aging-related degradation, such as softening, spheroidization, embrittlement, and creep. When cracks are found in these components, weld repair is often employed to ensure continued operation. The efficacy of the weld repairs in terms of extending the life of the aged components has, however, not been documented quantitatively. The Electric Power Research Institute (EPRI) has recently undertaken a comprehensive study to evaluate weld repairs performed to aged piping. In connection with this study, results from other worldwide activities have been reviewed, leading to significant conclusions regarding weld repair. This review of results from several worldwide studies has confirmed that aged high-temperature piping can be successfully weld repaired to gain additional lives in excess of several decades. The key aspects of successful weld repair include excavation and removal of all prior creep cavitation damage, elimination of external bending stresses, and implementation of good welding practice. From merely a creep rupture point of view, postweld heat treatment (PWHT) has been concluded to be superfluous by several authors. Temperbead repairs appear to offer a promising alternative to PWHT repairs from a creep, tensile, and toughness standpoint. Choice of the repair process ultimately is dictated by many considerations such as toughness, notch sensitivity, residual stresses and hydrogen embrittlement susceptibility. Several reports suggest that gas tungsten arc welding (GTAW) repairs may outperform shielded metal arc welding (SMAW) repairs with or without PWHT. [S0094-9930(00)02001-1]

Effect of Post-Weld Heat Treatment on Hardness in Superduplex Stainless Steel ASTM A890/A890M - Grade 6A

2020 ◽  
Vol 1012 ◽  
pp. 296-301
Author(s):  
Clélia Ribeiro de Oliveira ◽  
Eloá Lopes Maia ◽  
Solange T. da Fonseca ◽  
Marcelo Martins ◽  
Julián Arnaldo Ávila Díaz ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Arc Welding ◽  
Treatment Condition ◽  
Heat Treatment Condition ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Superduplex Stainless Steel ◽  
Secondary Austenite ◽  
Welding Processes

Superduplex stainless steel alloy exhibit high mechanical and corrosion resistance, which main industrial application is in the petrochemical industry. The manufacture and maintenance of such equipment usually involve welding processes, followed by post-welded heat treatment and it often becomes impossible to apply heat treatments. Thereby, the purpose of this work is to verify the effect of a post-welded heat treatment on shielded metal arc welding in steel grade ASTM A890/A890M - grade 6A. The microstructure in the as-welded condition consisted of austenite, secondary austenite, and ferrite phases and, the post-welded heat treatment condition exhibited only austenite and ferrite. The hardness in the melt zone reached values of 300 HV after welding and, the value was reduced to 260 HV in the post-welded heat treatment condition.

Effect of Postweld Heat Treatment on the Mechanical Properties of Weld in a Medium Carbon Steel

2013 ◽  
Vol 315 ◽  
pp. 6-10 ◽  
Author(s):  
S.M. Manladan ◽  
B.O. Onyekpe
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Steel ◽  
Postweld Heat Treatment ◽  
Medium Carbon Steel ◽  
Air Cooling ◽  
Shielded Metal Arc Welding ◽  
Medium Carbon ◽  
Before And After ◽  
Postweld Heat

This paper presents the result of an investigation of the effect of postweld heat treatment on the mechanical properties of weld in 0.36%C medium Carbon Steel. Samples were prepared and welded using Shielded Metal Arc Welding (SMAW) process with a low hydrogen electrode. The welded samples were subjected to postweld heat treatment (stress relief) at four different temperatures: 550°C, 600°C, 650°C and 700°C followed by air-cooling. Microstructural examination was carried out to determine the change in microstructure before and after postweld heat treatment. The mechanical properties of the samples were also tested before and after the heat treatment. It was established that a hard microstructure, susceptible to Hydrogen Induced Cracking (HIC), was formed in the heat affected zone of the as-welded samples and that postweld heat treatment improved the mechanical properties of the weld and substantially reduced or eliminated the risk of HIC.

scholarly journals Effect of PWHT Conditions on Toughness and Creep Rupture Strength in Modified 9Cr-1Mo Steel Welds

2019 ◽  
Vol 38 (2019) ◽  
pp. 739-749 ◽  
Author(s):  
Satoru Nishikawa ◽  
Tadayuki Hasegawa ◽  
Makoto Takahashi
Keyword(s):  
Arc Welding ◽  
Power Plants ◽  
Rupture Strength ◽  
Creep Rupture ◽  
Creep Rupture Strength ◽  
Shielded Metal Arc Welding ◽  
Fracture Appearance Transition Temperature ◽  
Metal Arc Welding ◽  
Fracture Appearance ◽  
Steel Welds

AbstractWe clarified the effect of post weld heat treatment (PWHT) conditions on the toughness and creep rupture strength of modified 9Cr–1Mo steel weldments used for high temperature components of ultra-supercritical power plants. Fracture appearance transition temperature (FATT) decreased as PWHT temperature increased, and for all of the weld metals of tungsten inert gas welding, submerged arc welding and shielded metal arc welding, FATTs were lower than 293 K when the PWHT temperature was higher than 1,008 K. In contrast, in the uniaxial creep test with a loaded stress of 108 MPa, the creep rupture strength of the specimen on which PWHT was carried out for a holding time of 7.2 ks was significantly decreased when the PWHT temperature was more than 1,033 K. Therefore, the appropriate PWHT temperature range to maintain the toughness and creep fracture strength was 1,008 K ≤ T ≤ 1,033 K.

scholarly journals The Effect of Cast Iron Preheating on the Microstructure of Welding Results by Using Cin-2 Electrodes

Teknomekanik ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 50-55
Author(s):  
Ahmad Sabirin ◽  
Purwantono Purwantono
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Weld Metal ◽  
Arc Welding ◽  
Shielded Metal Arc Welding ◽  
Affected Area ◽  
Weld Joints ◽  
Microstructure Observation ◽  
Metal Arc Welding ◽  
The One

Cast iron is commonly found in engineering tools such as machine frames, vise, lathes, planers, pressing tools, V-belt pulleys and others. Cast iron is a metal which is relatively difficult to weld because it contains more than 0.3% carbon. As a matter of fact, a lot of welding workers still experience failure in welding the cast iron, so they require the proper procedures to perform welding on the cast iron like the heat treatment before the welding. This study was aimed at obtaining the effect of preheating variations on the weld joints in which the process of welding the material used the type of open V seam connection. The specimen used was a cast iron with a thickness of 10 mm and the electrode used was the JIS Z 3252 DFCNiFe electrode. The method applied in this research was the microstructure observation testing toward the welding result by using Shielded Metal Arc Welding (SMAW). Based on the results of the study, it can be concluded that by applying the preheating variation treatment on the cast iron welding, there was a change in the microstructure and it was dominated by pearlite-ferrite in the weld metal area. As a result, the rough graphite that looks like roots became smooth after experiencing the preheating treatment because the ferrite was evenly distributed in the heat affected area. To conclude, the most superior specimen for the cast iron preheating among the four specimens was the one with 425oC temperature.

Applying of Heat Treatments to Improve the Properties of Welded Pipeline Steel

2019 ◽  
Vol 297 ◽  
pp. 143-150
Author(s):  
Kaltoum Digheche ◽  
Zakaria Boumerzoug ◽  
Farida Khamouli ◽  
Adel Saoudi ◽  
Khawla Saadi
Keyword(s):  
Heat Treatment ◽  
Arc Welding ◽  
Pipeline Steel ◽  
Weld Zone ◽  
Heat Treatments ◽  
Isothermal Heat Treatment ◽  
X Ray Diffraction ◽  
Shielded Metal Arc Welding ◽  
X Ray ◽  
Metal Arc Welding

This work, presents some heat treatments were used to improve the microstructure in different zones of the API X70 welded pipeline steel. In this study a shielded metal arc welding (SMAW) process has been realized.. Scanning electron microscopy and X-ray diffraction have been used as characterization techniques to observe the WM microstructures, in addition hardness are also measured. The results revealed that the isothermal heat treatment caused progressive recristallization reactions in the weld zone, and the hardness of weld joints decreased, were the main transformations after increasing the temperature of the heat treatment.

INCO-WELD B ELECTRODE

Alloy Digest ◽  
1984 ◽  
Vol 33 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Tensile Properties ◽  
Arc Welding ◽  
Base Alloy ◽  
Heat Treating ◽  
Alternating Current ◽  
Nickel Base Alloy ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Nickel Base

Abstract INCO-WELD B is a nickel-base alloy developed for shielded metal-arc welding of nickel steels for cryogenic applications. It is similar to INCO-WELD A Electrode (Alloy Digest Ni-305, November 1984) except that it is designed for use with alternating current to minimize magnetic arc blow. It can be operated in all welding positions. This datasheet provides information on composition and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-307. Producer or source: Huntington Alloys.

INCO-WELD C

Alloy Digest ◽  
1996 ◽  
Vol 45 (1) ◽  
Keyword(s):  
Tensile Properties ◽  
Stainless Steels ◽  
Arc Welding ◽  
Carbon Steels ◽  
Alloy Electrode ◽  
Shielded Metal Arc Welding ◽  
Medium Carbon ◽  
Metal Arc Welding ◽  
Spring Steels ◽  
Medium Carbon Steels

Abstract INCO WELD C Electrode is a stainless-alloy electrode especially designed for shielded-metal-arc welding of a broad range of materials, including many difficult-to-weld compositions. It can be used in stainless steels, mild and medium-carbon steels,and spring steels. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on joining. Filing Code: SS-632. Producer or source: Inco Alloys International Inc.

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