Steel pipe C-276 stainless steel pipe customized C276 stainless steel alloy pipe-C-276 steel pipe

Hastelloy C-276 alloy is a tungsten-containing nickel-chromium-molybdenum alloy that is considered corrosion-resistant due to its very low silicon-carbon content.

Performance against most corrosive media in both oxidizing and reducing atmospheres.

Resistant to pitting, crevice and stress corrosion. The higher Mo and Cr content makes the alloy resistant to chloride ion corrosion, and the W element further improves the corrosion resistance. At the same time, Hastelloy C-276 alloy is one of the few materials that are resistant to moisture chlorine, hypochlorite and chlorine dioxide solutions, and has corrosion resistance to high concentrations of chloride salt solutions such as ferric chloride and copper chloride. It is suitable for various concentrations of sulfuric acid solutions and is one of the few materials that can be applied to hot concentrated sulfuric acid solutions.

The physical properties of Hastelloy C-276 alloy are as follows:

Material composition: 57Ni-16Cr-16Mo-5Fe-4W-2.5Co*-1Mn*-0.35V*-0.08Si*-0.01C* * is a large a margin

Executive standards: UNS N10276, ASTM B575, ASME SB575, DIN/EN 2.4819

Density: 8.90g/cm3

Hastelloy C-276 alloy welding performance is similar to ordinary austenitic stainless steel, before using a welding method to weld C-276, measures must be taken to reduce the corrosion resistance of the weld and heat affected zone, such as tungsten gas shielded welding (GTAW), metal pole gas shielded welding (GMAW), submerged arc welding or other welding methods that can reduce the corrosion resistance of the weld and heat affected zone to a small extent. However, for welding methods such as oxyalkyne welding, which may increase the carbon or silicon content of the material, weld seam and heat-affected zone [2].

For the selection of welded joint form, refer to the successful experience of Hastyry C-276 alloy welded joints in the ASME boiler and pressure vessel specification.

Welding groove is good to use machining methods, but machining will bring work hardening, so it is necessary to grind the groove of machining before welding.

Suitable heat input speed should be used during welding to prevent the generation of thermal cracks.

In most corrosive environments, Hastelloy C-276 alloy can be used as weldments. However, in a very harsh environment, C-276 materials and weldments should be solved heat treated to obtain good corrosion resistance.

Hastelloy C-276 alloy welding can choose itself as a welding material or filler metal. If certain components are required to be added to the Hastelloy C-276 alloy weld, like other nickel-based alloys or stainless steel, and these welds will be exposed to corrosive environments, then the electrode or wire used for welding requires performance comparable to the base metal.

Solution heat treatment of Hastelloy C-276 alloy materials consists of two processes:

Heating at 1040°C~1150°C;

It is quickly cooled to a black state (about 400°C) within two minutes, so that the treated material has good corrosion resistance. Therefore, stress-relieving heat treatment of Hastelloy C-276 alloy alone is ineffective. Before heat treatment, clean up all dirt that may produce carbon during the heat treatment process, such as oil stains on the alloy surface.

The surface of Hastelloy C-276 alloy will produce oxides during welding or heat treatment, which reduces the Cr content in the alloy and affects the corrosion resistance, so it is necessary to clean the surface. A stainless steel wire brush or grinding wheel can be used, and then immersed in a mixture of nitric acid and hydrofluoric acid in an appropriate proportion to pickle, and then rinsed with clean water.