The heating of oil-quenched steel wire should use induction heating or electric contact heating technology. According to the information, for 50CrVA steel wires of the same heat number and the same size, the tube furnace and the electric contact method are used respectively. Heating to the same temperature, then oil quenching and tempering, the two steel wires have similar strength levels, but the steel wires heated by electrical contact have much better bending and torsion properties. This is because rapid heating changes the structure and grain size of the steel.
(5) On-line inspection eddy current flaw detection
In order to ensure the reliability of the steel wire, the finished steel wire must be subjected to on-line eddy current flaw detection, and a small number of individual defective parts should be marked for removal when winding the spring. So far, no oil-quenched steel wire manufacturer in my country has used eddy current flaw detection technology. First Twelve had imported equipment from Germany, but failed to put it into mass production.
(6) Market weight technology
In order to improve production efficiency, it is necessary to strengthen the research on rewinding equipment for the market. To meet the needs of spring enterprises.