AIL trucks produced in the Second Automobile Works(SAW), with annual capacity of 100,000 trucks, have adopted leaf springs with double-grooves incorporated on the compression side. A Silicon-Manganese-Vanadium-Boron grade steel (55SiMnVB) was developed with very low tendency of decarburization in heating and very good hardenability on quenching. With rational cross-sectional configuration, a reduction in weight of 10.5% of spring assembly is realized.SAW adopts unique induction heating of spring leaves. The exceedingly short time of heating further excludes the possibility of decarburization. Another unique technology is individual cooling of spring leaves. After tempering, spring leaves undergo pre-stressing shot-peening. The final process is electrostatic coating with infrared drying.China possesses the highest mountain ranges in the world with some very severe road conditions, the successful operation of over 500,000 AEOLUS trucks has well proved the success of this spring material and its processing technology.