Indian Welding Journal

Vishvesh J. Badheka ¹, S. K. Agrawal ²

Affiliations
1 Mechanical Engineering Department, School of Technology, Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382 009, IN
2 Fusion Resources, 93/6,Shreeji Ind. Estate, GIDC Makapura, Vadodara, IN

Abstract

Narrow gap welding is an effective process for joining thick plates (2" to 12") of carbon steel, low alloys steel and high strength low alloy steels. But it requires some development in torch design, wire feeding mechanism and welding procedure for preventing all sorts of weld defects before practical application. Narrow gap welding technology is associated with various conventional arc welding technology like GMAW, GTAW, SAW, FCAW&SMAW. Several fabricators world over, especially in Japan have developed their own equipment working on different principles [1]

Standard torches for NGW are not available routinely in the market. Torches for NGW are specially designed (custom made) for various NGW applications. Design of torch will differ from processes to process and application to application. Paper highlights the different torch designs used by researcher for different narrow gap welding technologies like

I) Narrow Gap-Gas Metal Arc Welding (NG-GMAW) Torch Design

II) Narrow Gap-Gas Tungsten Arc Welding (NG-GTAW) Torch Design

III) Narrow Gap- Submerged Arc Welding (NG-SAW) Torch Design.

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M. N. Patel ¹, S. K. Agrawal ¹

Affiliations
1 Metallurgical Engineering Department, M. S. University of Baroda, Baroda-1, IN

Abstract

Austenitic Stainless Steels are characterised by high content of chromium (18-20%) and nickel (8-14%) present in the solution and which impart the characteristic corrosion resistance property to this variety of steel.

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Vishvesh J. Badheka ¹, S. K. Agrawal ², Umang Parikh ³

Affiliations
1 Metallurgical Engineering Department, The M.S.University of Baroda, IN
2 Fusion Resources, 925/2/8, GIDC Makapura, Vadodara, IN
3 Anup Engineering, Ahmedabad, IN

Abstract

Hot cracking refers to cracking that occurs during welding, casting or hot working at temperatures close to the melting point of the materials. Hot cracking susceptibility of austenitic stainless steel is a problem arising during welding of austenitic stainless steels, particularly in fully austenitic and stabilized compositions. Hot cracking in stainless steel welds is caused by low-melting eutectics containing impurities such as S, P and alloy elements such as Ti, Nb. In stabilized stainless steels, Ti and Nb react with S, N and C to form low melting eutectics. In austenitic stainless steels, segregation plays an overwhelming role in determining cracking susceptibility. Total crack length (TCL), has been used extensively as hot cracking parameter. [1,2]

In the present investigation, an attempt has been made to study hot cracking susceptibility of stabilized ASS on transvarestraint test unit, with acidic and basic coated electrodes.

Experiment, shows that acidic and basic coated electrodes both are more or less equally susceptible to hot.

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S. K. Agrawal ¹

Affiliations
1 Metallurgical Engg., M. S. University of Baroda, Vadodara - 390001, IN

Abstract

Aluminium alloys find wide applications in all kind of industries. Emphasis on lighter vehicles has especially encouraged use of aluminium in transport sector and in automobile industry. Lower density is the prime reason for their preference in this sector but good thermal conductivity is another major consideration some applications. Transport sector accounts for nearly 18% of the total aluminium consumption in India.

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S. K. Agrawal ¹, M. N. Patel ¹

Affiliations
1 Metallurgical Engineering Department, M, S. University of Baroda, Vadodara, IN

Abstract

Two low ferrite filler wires and one autogenous weld were tried on 316L Stainless Steel sample plates, lor assessing the hot cracking susceptibility. The deposited welds were tested for ferrite number and the autogenously melted using TIG process on Transvarestraint testing unit. These samples were strained at two different levels. The hot cracking susceptibility was measured in terms of number of cracks, total length of cracks and maximum crack length at two different strains to the weld metal. It was found that the total crack length or number of cracks are indicative of cracking susceptibility. Interestingly, order of increasing susceptibility in the welded samples matched with the decreasing level of delta ferrite.

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