Spring steel is a metal workpiece with high economic value in the industrial market.spring steel strip heating equipment is mainly used to manufacture disc spring, waveform spring and spiral spring, and so on. Heat treatment can improve its mechanical properties and service life, etc.
Due to the different state, spring steel strip (plate) can be divided into two categories: annealed steel strip (< 200HV), cold rolled steel strip, one of which is semi-hard state (230~270HV), the other is full hard state (≤ 33HRC). Heat-treated steel has quenched and tempered (quenched, tempered) and bainitic steel strips. The steel grade and chemical composition of spring leaf sheet (YB543) shall be in accordance with YB-59. All springs made of this kind of material must be heat-treated by induction heating equipment in order to obtain the required mechanical properties.
There are two kinds of heat treated spring steel: quenched and tempered steel strip and isothermal quenched lower bainitic steel strip. They are all produced in continuous working furnaces. When the induction heating equipment is used for heat treatment, the heating temperature of the steel strip is not measured, but the furnace temperature at the inlet and outlet of the quenching heating furnace and the tempering bath furnace are controlled. For example, the temperature at the inlet of the induction heating equipment is 840 ℃ and the temperature at the outlet is 930 ℃ when the speed of operation is 8m/min for TlOA steel strip with thickness of about 0.3mm. After the steel strip is heated, the bainite isothermal quenching or direct oil quenching is carried out in a lead-antimony alloy bath furnace with a temperature of 320 ℃, and then, according to the required strength level, a continuous tempering is carried out in the bath furnace at 380 ℃ / 580 ℃. According to the national standard, the strength of heat-treated spring steel strip is divided into 1, 2 and 3 grades. The spring made of quenched and tempered or lower bainitic steel strip does not need to be quenched-tempered, but can only be annealed without stress.
Overseas manager: Tom Wang
Phone: 0086-13303078975(whatsapp, wechat,line)
Specialist of bar heat treatment furnace in China; Glad to be your business partner in induction heating field.
Post time: 04-27-2019