Annealing type of spiral steel pipe 

1. Spheroidizing annealing

Spheroidizing annealing is mainly used for hypereutectoid carbon steel and alloy tool steel (such as steel used for manufacturing cutting tools, measuring tools, and molds). Its main purpose is to reduce hardness, improve machinability, and prepare for future hardening.

2. Stress Relief Annealing

Stress relief annealing is also called low temperature annealing (or high temperature tempering). This annealing is mainly used to eliminate residual stresses in castings, forgings, welded parts, hot rolled parts, cold drawn parts, etc. If these stresses are not eliminated, the steel parts will be deformed or cracked after a certain period of time or during the subsequent cutting process.

3, complete annealing and isothermal annealing

Complete annealing is also called heavy crystallization annealing, generally referred to as annealing. This annealing is mainly used for casting, forgings and hot-rolled profiles of various carbon steels and alloy steels with

sub-eutectoid components, and sometimes also used for welding structures. Generally used as the final heat treatment of some non-heavy workpieces, or as a pre-heat treatment of some workpieces.