Alloy 825 Seamless Pipe

Chemical constituents

Ni: 38.0%-46.0%, Cr: 19.5%-23.5%, Fe: balance, C: ≤ 0.025%, Mn: ≤ 1.0%, Si: ≤ 0.5%, Mo: 2.5%-3.5%, Cu: 1.5%-3.0%, Co: ≤ 1.0%, Al: ≤ 0.2%, Ti: 0.6%-1.2%

Physical properties

Density: 8.14 g/cm³

Melting point: 1370-1400℃

Mechanical properties of Alloy 825 seamless pipe (at room temperature) 

Solution treatment

Tensile strength (Rm): 549MPa

Yield strength (Rp0.2): 241MPa

Elongation(A%): 30%

Brinell hardness: ≤ 200HB

Characteristics

● Good stress corrosion cracking resistance

● Good resistance to pitting corrosion and crevice corrosion

● Good oxidation resistance and non oxidizing thermal acid performance

● Good mechanical properties at room temperature and high temperature up to 550 ℃

● Certification of pressure vessels with manufacturing temperature up to 450 ℃

Application fields

Alloy 825 seamless pipe is widely used in various industrial fields where the service temperature is less than 550 ℃.

● Typical applications are:

● Heating pipes, containers, baskets and chains for sulfuric acid pickling plant.

● seawater cooling heat exchanger, marine product pipeline system, sour gas environment pipeline.

● Heat exchanger, evaporator, washing, impregnating tube, etc. in phosphoric acid production.

● Air heat exchanger in petroleum refining

● Food Engineering

● Chemical process

● Flame retardant alloys for pressurized oxygen applications

Welding process

Alloy 825 seamless pipe is suitable for welding with the same material or other metals by any traditional welding process, such as tungsten inert gas welding, plasma arc welding, manual sub arc welding, metal inert gas welding, and melting electrode inert gas welding. Pulse arc welding is the preferred scheme. When manual arc welding is used, it is recommended to use (Ar + He + H2 + CO2) mixed shielding gas.

The welding of Alloy 825 seamless pipe must be carried out in annealed state, and the stains, dust and marks shall be cleaned with stainless steel wire brush. In order to obtain the best root weld quality, the operation must be very careful (argon 99.99), so that no oxide will be produced in the weld after the root welding. The color produced in welding heat affected zone shall be removed by stainless steel brush when the weld area is not cooled.

Welding material:

For the following gas shielded welding processes are recommended

Metal electrode:

Nicrofer S 6020-FM625, Material No. 2.4831

SG- NiCr21Mo9Nb, AWS A5.14: ERNiCrMo-3

Electrode material No. 2.4621, EL- NiCr20Mo9Nb, AWS A5.11: ENiCrMo-3

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