Jiu Sheng Spring
(1) cold rolled extension springs are generally de-stress annealed after molding, and their hardness is not assessed, according to the requirements of the use is also allowed to not carry out the stress annealing;
(2) need to be quenched and tempered cold rolled springs, the number of quenching times not more than two, tempering times are not limited to the hardness value of the 42-52HRC range to choose, in special cases its hardness can expand the range of 55HRC. Hardness can be expanded to 55HRC. annealed cold hardened beryllium bronze cold coiled springs need to be quenched and aging treatment, the number of quenching shall not exceed two times, the number of aging is not limited.
(3) hot coil extension spring hardness after quenching and tempering, generally 41.5-48HRC. unilateral decarburization layer depth is allowed for the depth of raw material standards and then increase the diameter of the material by 0.5%;
(4) hot coil spring molding, it must be uniform heat treatment, that is, quenching, tempering;
(5) where the spring surface plating is zinc (5) Where the spring surface plating is zinc, chromium and cadmium, plating should be dehydrogenated after treatment.