Studies On High Toughness Multi Eelement Alloys Wear-Resisting Steel

In view of manufacturing of hammer crusher, linings and miningmachinery materials must have high hardness, good toughness characteristics.This paper developed two wear-resistant steels: low carbon alloy steel andmedium carbon alloy steel.In the chemical composition, in order to ensure that the wear resistantsteel has high harden ability and good toughness, for low carbon alloy steel,adjustment Ni content to1.0%and adjustment Mo content to0.5%,forwear-resistant alloy of carbon steel, they are0.5%and0.3%. Due toparticularity of wear-resistant materials service condition, material needs tohave good corrosion resistance. Medium carbon alloy steel contains0.597%Cu, which increase the electrode potential to enhance the corrosion resistanceperformance of material.In the preparation process, use RE-Si-Ca and titanium iron for meltingsteel’s compound modification treatment, then for casting reasonableannealing, quenching and tempering treatment. For processed sample, heretest the hardness, impact toughness, and with scanning electron microscopyhas an analysis of the impact specimen fracture morphologies and wearsurface morphology.The experimental results show that new steels under thecorresponding heat treatment conditions have good wear resistance andcorrosion resistant, under different conditions they can satisfy wear-resistantmaterials’ performance requirements. The results showed that new materialshave high harden ability and good comprehensive mechanical properties, thelow carbon alloy steel’s fracture morphology showed a lot of dimple forductile fracture. On the morphology of worn surface， it belongs to themicro-cutting and plastic fatigue wear. The fracture morphology of mediumcarbon alloy steel is large amounts of cleavage and quasi cleavage fracture.They have low toughness, high hardness and brittle fracture, the form ofwear is usually fatigue spalling and brittleness breaking off.（1）After heat treatment for the thick section steel, the metallographic of lowcarbon alloy steel was made up of lath marten site and a small amount of carbondioxide which was dispersion distribution; the microsructure of medium carbon alloy steel concluded a large numbers of lath marten site, a small quantity of plate martensite, retained austenite and carbon dioxide. It ensures that the steel has goodcomprehensive mechanical properties. After quenching at960℃for3hours andtempering at260℃for4hours, The hardness of low carbon alloy steel reachedHRC48.74and the impact toughness got above αKV=42.47J/cm~2; after quenching at910℃for3hours and tempering at370℃for4hours, medium carbon alloy steel hasgood comprehensive mechanical properties with hardness HRC48.94and impacttoughness αK=34.67J/cm~2.（2）In the same impact abrasive wear, because of the hardness of low carbonalloy steel lower than medium carbon alloy steel, Its had high wear rate and poor wearresistance.（3）Corrosion experimental results verified corrosion resistance performance oftwo kinds of steel. In the5%HCl solution, the two kinds of steel corrosion belongedto chemical corrosion and corrosion rate was high. Because of the passive ability ofchromium in the low carbon alloy steel was failed to show, and corrosion resistance ofthe materials was enhanced. because copper improved the electrode potential ofmedium carbon alloy steel，so the corrosion rate of low carbon alloy steel was twiceas likely as medium carbon alloy steel. In the5%NaOH and5%NaCl solution, thecorrosion of two steels was electrochemical corrosion. Because NaCl solutioncotained Cl－which was easily to cause corrosive pitting, so the corrosion rate waslargish. Simultaneously the corrosion rate was much more minor than the corrosion inthe HCl.