奥锰钢材料孕育变质工艺研究与应用开发

【作者】 周志荣；

【导师】 颜银标； 章成希；

【作者基本信息】 南京理工大学 ， 材料工程， 2007， 硕士

【摘要】 常用球磨机衬板有奥锰钢衬板和中碳合金钢衬板等,奥锰钢衬板韧性好,但初始硬度不足;而中碳合金钢硬度高,但韧性差。本文针对现有奥锰钢材料性能的不足,通过化学成分设计和微合金化,选用合适的孕育剂和变质剂进行双变质处理,获得了同工况条件下耐磨性能比传统耐磨钢提高达50%-100%以上的高性能耐磨奥锰钢;通过分析孕育、变质处理奥锰钢组织形态、成分分布和综合性能特点,探讨了孕育剂、变质剂在奥锰钢中的作用机制,为进一步改善奥锰钢孕育变质效果、提高奥锰钢耐磨性能提供了理论基础和生产控制方法。根据碳、锰在奥锰钢中的作用机理,使用工况条件,以及Mn和C之间的经验关系,确定中锰钢的Mn含量在5.5-7.5%,C含量在1.0-1.4%;高锰钢的Mn含量11.0-14.0%,C含量在0.90-1.20%。其余元素Si、Cr、P含量分别在0.3-0.6%、1.5-2.5%、≤0.04%,杂质元素S≤0.04%。另外,还采用了B、Nb、N等进行微合金化,以细化晶粒。采用稀土RE-Ca-Ti-Al复合变质剂、V_渣—Ti—Zn复合孕育剂和对奥锰钢进行微合金化处理,显著改变了碳化物的数量、大小和形态分布;明显提高了在奥氏体基体上分布的均匀性;减少和改善了非金属的数量和分布状态;细化了奥氏体晶粒,显著的减少了由于碳化物的溶解所留下的显微裂纹。这些特征的改变均明显的提高了奥锰钢工件的综合力学性能及其耐磨性能,并且由于韧性的提高,适度提高碳含量,使工件的磨后硬度显著提高。分级复合孕育变质处理不仅能提高钢液的冶炼处理质量,也能提高抗孕育衰退能力,对厚截面的大型铸件,实施微合金化处理可解决由铸造过程和热处理过程中产生的粗晶现象和促进其表层与心部组织的一致性。根据上述合金成分设计及双变质处理,所得奥锰钢力学性能和耐磨性能均有较大的提高,尤其是中锰钢材料,σ_b由变质前的793MPa提高到916MPa,α_k由46J/cm~2提高到76J/cm~2,磨后硬度由693Hv提高到768Hv,相对耐磨系数β由1.78提高到2.63;这主要的原因是中锰钢除具有高锰钢和超高锰钢所具有的碳的固溶强化和碳化物的弥散强化外还易产生大量的应力诱变马氏体,从而使其加工硬化速率提高,加工硬化效果更为显著。更多还原

【Abstract】 Commonly used ball mill backing has the high manganese steel backing and the carbon alloy steel backing and so on,high manganese steel backing toughness is good,but the initial degree of hardness is insufficient;But carbon alloy steel degree of hardness is high,but toughness is bad.This article in view of the existing Austria manganese steel material performance insufficiency,through the chemical composition design and the micro alloy,selects the appropriate inoculant and the alterant carries on double deterioration processing,obtained under the same operating mode condition the wear-resisting performance to be wear-resisting the steel compared to the tradition to raise reaches as high as 50%-100%above high performance Austria manganese steel;Through analyzes the double deterioration to process the Austria Manganese steel Organization shape,the ingredient distribution and the performance characteristic,has discussed the inoculant,the alterant in Austria manganese steel function mechanism,for further improved the Austria manganese steel molten steel double deterioration effect,enhances the Austria manganese steel performance to provide the rationale and the instruction.According to carbon,manganese in Austria manganese steel action mechanism,use operating mode condition,as well as between Mn and C empirical relationship,in determination manganese steel Mn content in 7.5-11%,C content in 1.15-1.2%;High manganese steel Mn content 11.0-14.0%,C content in 0.90-1.20%.Other element Si,Cr,P content separately in 0.3-0.6%,1.5-2.5%,≤0.04%,impurity element S≤0.04%.Moreover, but also used B,Nb,N and so on has carried on the micro alloy,by refinement crystal grain.Using the rare earth RE-Ca-Ti-Al compound alterant,V dregs-Ti-Zn compound inoculant carries on micro alloy processing to the Austria manganese steel,obviously changed the carbide quantity,the size and the shape distribution;obviously enhanced the uniformity which distributes in the austenite substrate;Reduced and improved the nonmetallic quantity and the distributed condition;Refinement austenite crystal grain, remarkable reduction because the carbide fuse stays behind micro crack.These characteristic change distinct enhancement Austria manganese steel work piece comprehensive mechanics performance and wear-resisting performance,and as a result of the tough enhancement,in enhances the carbon content moderately in the foundation, because sharpened the work hardening ability,after causes the work piece to rub the degree of hardness remarkable enhancement.Not only grades compound double deterioration processing to be able to enhance the molten steel the smelting processing quality,also can sharpen the anti-breeding decline ability,to the thick section heavy casting,implements micro alloy processing to be possible to solve the macrocrystailine phenomenon which produces by in the casting process and the heat treatment process and to promote its surface layer and the heart department organization’s uniformity.According to the above alloying constituent design and double deterioration processing,the obtained Austria manganese steel mechanics performance and the wear-resisting performance have the big enhancement,in particular the manganese steel material,σb enhances 916MPa from deterioration before 793MPa,αk enhances 76J/cm2 from 46J/cm2,after rubs degree of hardness to enhance 768Hv from 693Hv,the relatively wear-resisting coefficientβfrom 1.78 enhances to 2.63;This main reason is the manganese steel besides has the carbon melting strengthening and the carbide dissemination which the high manganese steel and the superelevation manganese steel have strengthens also easy to produce the massive stress mutagenesis martensite,thus makes its work hardening speed to enhance,the work hardening effect is more remarkable.更多还原