Welding of Hastelloy C276 alloy(HY industry- Technical Center internal data)

Hastelloy C-276, UNS N10276, referred to as C276, one of the most common nickel-based corrosion-resistant alloys

Applicable to a variety of chemical industries containing oxidizing and reducing media. Higher molybdenum and chromium contents make the alloy resistant to chloride ion corrosion, and tungsten further improves corrosion resistance. Hastelloy C-276 is one of only a few materials resistant to moisture chlorine, hypochlorite and chlorine dioxide solutions. It has significant properties for high concentrations of chloride solutions such as ferric chloride and copper chloride. Corrosion resistance.

 

Introduction to difficulties in argon arc welding of C276

  • The surface of Hastelloy C-276 alloy will produce oxides during welding or heat treatment, which will reduce the Cr content in the alloy and affect the corrosion Hastelloy C276 resistance, so it should be surface cleaned. A stainless steel wire brush or a grinding wheel can be used, followed by immersion in a mixture of nitric acid and hydrofluoric acid in an appropriate ratio, and finally rinsed with water.

 

 

  • The Hastelloy-based alloy weld pool is very viscous and has a shallow penetration. Increasing the welding current does not significantly improve the fluidity of the metal and increase the penetration.

 

 

  • During argon arc welding operation, the welding consumables should not be directly immersed in the molten pool. The welding consumables should be placed in front of the tungsten poles and fed while melting. The ends of the consumables are always protected by argon. Hastelloy-based nickel-based consumables have poor fluidity and current should not be too large, the welding speed is slow, and the welding should be finely controlled.

 

 

  • When welding, whether it is bottom welding, interlayer welding, or cover welding, the back of the welding must be argon-protected to prevent the welded part from being oxidized. The welded argon must be welded with high Hastelloy C276 purity argon. When the argon is protected, the gas flow rate should not exceed 15L unit flow, otherwise the gas flow in the weld pool will be disturbed and disturbed to the protection of the inert gas.

 

 

  • Argon arc welding can only be welded by scooping. It is not possible to use an excessively wide rocker to weld the method. Otherwise, severe thermal creep variables will be exceeded, resulting in large-scale internal extension cracks. Moreover, Hastelloy belongs to special welding, and the excessive walking method will also affect the oxidation of the internal finished primer.

 

 

 

  • Water is required between the weld layers to control the temperature above the crystal line.

Pay attention to the point:

  • The ERNiCrMo-4 welding wire was selected for the welding consumables and the welding rod was made of ENiCrMo-4. This kind of welding wire has excellent corrosion resistance and process performance. Its chemical composition is similar to that of the base metal and its manganese content is higher than that of the base material. It can improve crack resistance and control pores during welding. Particularly ultra-low carbon plays a role in preventing intergranular corrosion.

  • In order to reduce the welding heat input, a small welding current is used as much as possible, and the welding method is performed by the rapid welding method. In addition, since Hastelloy is easy to crack at the arc-receiving position, it is necessary to fill the arc pit when the arc is closed, and the previous arc pit should be polished before re-arc welding, and then cleaned with a soft brush. Subsequent welding. These two treatments can suppress the generation of hot cracks.

HY-industry is qualified superalloy supplier.We have more than 20 years experience in kind of  Inconel, Monel,incoloy,Hastelloy production.

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