hastelloy C-4——Thermal processing, cold working, heat treatment and welding performance

A hot processing
This alloy does not contain W, so its high temperature deformation resistance is reduced. It is easier to hot work than the above two high Mo-containing Ni-Cr-Mo-W alloys, and the hot working temperature range is the same as hastelloy C-276.
B cold working
Hastelloy C-4 alloy has good cold workability and can smoothly produce metallurgical products that require cold processing. Since the aging treatment does not produce a change in alloy plasticity, the aging state has a uniform cold formability with the solid solution state (Table 8-42).

Table 8-42 Cold Formability of Hastelloy C-4 Alloy

C heat treatment
The solid solution of hastelloy C-4 alloy has the best corrosion resistance and the highest plasticity. The solution treatment temperature is lower than that of the former two Ni-Cr-Mo-W alloys, which is 1040 ~ 1080 °C, and it is quenched after heating and holding. The softening intermediate annealing temperature of the cold working is also preferably carried out at this temperature.
D welding
The hastelloy C-4 alloy has good weldability, and since the alloy has extremely high thermal stability, the corrosion resistance after welding does not tend to deteriorate, so it can be used directly in the welded state. This alloy can be welded by conventional welding methods other than acetylene welding. TIG, MIG and manual welding arcs are all without any difficulty. When using submerged arc welding, C and Si are not allowed in the flux and care should be taken to prevent overheating. The filling metal can be made of the same material as the base material, or a matching welding material with a slightly higher Cr or Mo.