PENINGKATAN KEKAKUAN PEGAS DAUN DENGAN CARA QUENCHING AIR GARAM

Abstract

This study is on the Effect of quenching on the leaf spring. This study also to investigate the chemical composition , the phase of the steel, values of impact and hardness of the leaf spring. The leaf speing to be investigate on the Mitsubishi L 300. The effect of quenching will be increase the elasticity. Materials tested on the chemical composition, impact value, microscopic structure, and the hardness. Temperature of austenization werebe 950 °C and at 30 minutes holding time. Media quenching are : salt water, brine water, lubricant oil and annealing. The stuy result area, on chemical composition C = 0,300 %, Fe = 97,07 %; Si = 1,292 % and Mn = 0,735 %. The steelphase on raw material are ferit, fine perlit and bainit, on the quenching salt water we havefine martensite, brine water quenching we find coarse martensit and carbide at the grain boundaries, quenching in lubricant oil we find martensite and carbides on the grain boundary and austenite , annealing will be phased perlite and ferrite. The hardness is 598,75 VHN on the salt water. 592,98 VHN, on the brine water quenching, and 569,63 VHN on the oil quenching, raw material at the 409,31 VHN and 222,176 VHN on the annealing process. The value of impact is 0,278 J/mm2 on full annealing, 0,193 J/mm2, on the raw material, 0,075 J/mm2,on oil quenching, 0,04 J/mm2 on brine water quenching, and 0,028 J/mm2. on the salt water quenching.