H13模具钢模铸坯夹杂物及碳化物分布解析

H13(4Cr5MoSiV1)钢是目前使用量最大的一种热作模具钢，钢中夹杂物和碳化物是影响性能及服役寿命的关键因素。实验在Thermo-Calc热力学软件分析基础上，采用金相显微镜、扫描电子显微镜、非水溶液电解装置等装备对某厂H13模铸坯中夹杂物、碳化物的分布规律进行解析。研究表明：夹杂物在H13模铸坯边部至中心，等效直径D≤3μm的小尺寸夹杂物逐渐减少，D≥5μm的大尺寸夹杂物逐渐增加，夹杂物的等效直径由2.82μm增大至3.86μm,密度由177个/mm²减少至47个/mm²,面积占比[0.057%,0.098%];夹杂物类型以MnS和Al₂O₃为主，检测结果与计算结果一致；H13碳化物从边部至心部，形态演变规律为：颗粒状、块状、片状、长条状，尺寸从几微米至100μm不等；主要为深灰色富V类MC型碳化物、亮白色富Mo类M₆C型碳化物、浅灰色富Cr类M₂₃C₆型碳化物。     

H13热作模具钢的热处理

测定了Ｈ１３钢的临界点和退火用ＴＴＴ曲线,研究了热处理工艺对Ｈ１３组织和性能的影响,试验结果表明,Ｈ１３钢在８４０￣８６０℃退火,软化效果最好,在１０２０￣１０４０℃加热淬火,５８０￣６００℃回火,可满足热作模具钢的硬度要求。     

转炉冶炼热作模具钢H13的生产实践

H13(4Cr5MoSiV1)钢是一种应用广泛的热作模具钢,是制造热锻模、热挤压模和压铸模的主要材料.H13钢通常由特殊钢厂采用电炉冶炼、电渣重熔和锻压工艺生产,质量较为稳定.但该制造工艺复杂、生产周期长、成本高、产量低.介绍了通过大型转炉冶炼和初轧轧制流程开发H13的新工艺,解决了生产过程中存在的一些质量问题,并对H13的实物质量水平进行了评估,各项性能指标接近国外先进水平.     

LF精炼炉渣成分对H13钢中夹杂物的影响

对早期失效的H13钢材进行了金相分析。结果表明:H13钢中大尺寸夹杂物数量多,夹杂物评级达不到要求,影响了H13钢材的使用性能。采用优化精炼炉渣成分的方法来控制钢中夹杂物数量和尺寸。使用优化的精炼炉渣后,在真空处理结束时测得钢液中T[S]、T[O]含量分别为5×10-4%和1.29×10-3%;夹杂物级别明显降低,钢中大尺寸夹杂物的数量和尺寸都有显著下降,大大提高了钢材的冶金性能。     

热作模具钢H13生产工艺实践

H13是一种具有良好的性价比及工艺性能的热作磨具钢,目前在国内外得到广泛应用,该钢种热裂纹敏感性强,对纯净度、内部质量等指标要求严格.韶钢根据热作模具钢H13的成分、产品特性及自身生产工艺装备,设计了"转炉—LF精炼—RH真空处理—大方坯连铸—入坑缓冷—轧制—检验、入库"生产工艺流程,通过转炉双渣操作、出钢渣洗预脱氧、LF高碱度渣精炼、RH长时间高真空脱气、连铸弱冷等工艺措施,成功开发出各项性能均能满足客户要求的H13圆钢产品.     

H13热作模具钢的应用

H13(4Cr5MoSiV1)热作模具钢是首钢特殊钢公司根据美国标准钢号H13开发的一种使用温度在600℃以下的中碳中铬热作模具钢。H13既具有3Cr2W8V钢的高温性能,又具有5CrMnMo钢高韧性的特点,也具有一般热作模具钢要求的较高的热硬性、热强性、抗回火稳定性、耐磨性、抗冷热疲劳性等。现已在锤锻模、挤压模、压铸模、模锻模等     

技术研发中心成功开发出H13热作模具钢

H13热作模具钢为美国牌号，主要用于制作较高温度下的模具材料，具有优良的综合力学性能，良好的抗热疲劳性能、热稳定性、抗氧化和耐液态金属冲蚀性能，以及良好的淬透性，是制造热作模的首选材料。国内模具钢主要生产厂家为长城特钢、辽特集团、上钢五厂，这三家钢厂的热作模具钢产量占到全国热作模具钢产量的50％。H13模具钢自今年以来，市场价格大幅上扬，为进一步拓宽莱钢产品市场，     

转炉连铸生产热作模具钢H13的工艺实践

介绍了鞍钢开发的热作模具钢H13的工艺流程,包括采用转炉双联冶炼、大罐合金烘烤、LF高碱度精炼渣、连铸弱二冷水控制等工艺措施。实践表明,H13钢转炉连铸连轧生产工艺可行,其成分、纯净度和低倍组织均达到了用户及NADCA#207-2003标准要求。     

H13热作模具钢圆铸坯的水平连铸工艺

随着我国模具工业的快速发展 ,模具钢产量增长极快 ;新型热作模具钢Ｈ1 3以高质量、高性能的特点得到大力推广开发[1] 。本文叙述了北满特殊钢公司双流水平连铸机连铸Φ1 5 0Ｈ1 3模具钢电渣母材的主要工艺参数和铸坯质量。1　技术条件和工艺流程Ｈ1 3钢是近 1 0余年应用最广、综合性能最好的中合金铬系热作模具钢[2 ] ,化学成分见表 1。表 1　热作模具钢Ｈ13的化学成分 %Ｔａｂｌｅ 1　Ｃｈｅｍｉｃａｌｃｏｍｐｏｓｉｔｉｏｎｏｆｈｏｔｗｏｒｋｉｎｇｄｉｅｓｔｅｅｌ %ＣＳｉＭｎＰ ,ＳＣｒＭｏＶＣｕ0 .34～0 .450 .80～1.2 00 .2 5～…     

高品质H13模具钢质量研究与分析

通过叙述高品质H13模具钢生产关键技术,并对比检测了国内外几家H13模具钢的成分、非金属夹杂物、显微组织、横向强度和冲击功等指标,莱钢模具钢质量已经达到或超过国外进口钢材水平。     

美标H13热作模具钢的锻造工艺优化

莱钢开发了美标H13热作模具钢并对锻造工艺进行了优化,优化后的锻造工艺采用三火成形,加热温度1260℃,锻造过程合理控制砧宽比、料宽比等工艺参数,提高锻件中心压实效果,锻后快冷并采用合理的球化退火工艺抑制网状碳化物析出,组织均匀,锻件的各项技术指标均完全满足技术要求。     

Inclusion Variations of Hot Working Die Steel H13 in Refining Process

 Inclusion variations of die steel H13, including changes of species, morphologies, compositions, amounts and sizes, in the production of EAF→LF→VD→ingot casting→electro-slag refining (ESR) procedure, were investigated by systematic sampling, and analyzed with scanning electron microscope (SEM), energy dispersive spectrum (EDS), and metallographic microscope. The variation mechanism was studied by comprehensive analysis of total oxygen, nitrogen, and acid soluble aluminum as well as chemical test of refining slag. Based on the investigations, technical measures for cleanness improvement were discussed. The results show that oxide inclusions in H13 steel change from irregular Al2O3→near globular CaO-MgO-Al2O3 and CaO-Al2O3-SiO2 complex inclusions→finer CaO-Al2O3-SiO2 inclusions with higher CaO content→CaO-Al2O3-SiO2 inclusions with higher Al2O3 content and irregular MgO-Al2O3 inclusions→fine irregular MgO-Al2O3-CaS inclusions in various steps of the production; the variations are related with changes of acid soluble aluminum content, reactions between slag and steel, re-oxidation of liquid steel during casting, and refining of ESR. It is also found that Al2O3 inclusions are modified by refining slag in LF and VD refining; and ESR plays a good role in inclusion removal, especially in controlling the large linear VC-CrC-MoC inclusions distributed in grain boundaries. It is suggested that casting protection should be improved, and the basicity of refining slag and acid soluble aluminum content in steel should be raised.     

Prediction and Analysis on Oxidation of H13 Hot Work Steel

The understanding of oxidation behaviors on H13 steel was helpful to improve the service life and performance of hot work moulds and dies. Thermal-Calc Software was performed to calculate the oxidation phases on H13 steel along with different partial oxygen pressures in the interesting temperature range of 500-700 ℃. In this range H13 steel samples were treated respectively in different atmosphere including flowing water vapor （0.2 MPa）, normal pressure air （0.1 MPa） and low pressure air （0. 001 MPa）. The different oxidation films were detected with optical microscopy and X-ray diffraction. The microstructures and phase constitutions of the films formed in low pressure air were similar to those of the films formed in water vapor, and obviously different to those of the films formed in normal pressure air. The oxidation mechanisms of H13 steel in different atmosphere were also discussed.     

影响H13热作模具钢等向性的因素

 通过显微组织和断口分析并与化学成分分析和力学性能测试相结合的方法,研究了H13钢铸态组织特征、碳化物类型和分布对等向性能的影响。结果表明：在冷却过程中,H13钢铸锭会产生严重的宏观元素偏析,在铸锭的个别区域,特别是最后凝固的中心区域,出现的少量不平衡亚稳定共晶碳化物、宏观偏析严重的铸态组织经变形而形成的带状组织、缓慢冷却形成的二次碳化物网是影响H13钢等向性的主要因素。     

Microstructure and Properties of Hot Working Die Steel H13MOD

Compared with H13 steel, the influences of different heat treatment process on the microstructure and properties of the new type of hot working die steel H13MOD were studied. The results show that the complete austenitizing temperature of H13MOD is around 1030 °C and the quenching hardness achieves the maximum value at this temperature. While for H13, the complete austenitizing temperature is above 1100 °C and the quenching hardness rise constantly with the quenching temperature increasing. In quenching process, the undissolved MC carbides can prevent the coarsening of grain in both steels. With the rise of quenching temperature, when MC carbides dissolve completely, the grain grows quickly. The hardness and strength of H13MOD at higher tempering temperature (above 570 °C) are nearly the same as those of H13, but its toughness is higher than that of H13. Mo₂ C carbide is the main strengthening phase in H13MOD, which is attributed to the higher content of Mo. The quantity of VC eutectic carbides is reduced because of lower content of V in H13MOD, which plays an important role in enhancing the impact toughness of H13MOD. Under a certain strength condition, H13MOD steel can be used in the environment that higher toughness is required and the service life of die casting mold can be improved.     

Effect of Niobium on Microstructure of Cast AISI H13 Hot Work Tool Steel

The effect of niobium addition on the microstructure of cast AISI H13 hot work tool steel was evaluated by using EDX analyzer attached to the scanning electron microscope. The volume percent of eutectic area and eutectic cell size and also volume percent of different carbides of new steel, which is heat treated under different conditions, are also determined. The results show that the a niobium addition modifies the cast structure of Nb-alloyed hot work tool steel, and reduces the size and volume of eutectic cells, and increases the maximum hardness of the steel.     

影响RH13质量稳定性因素探讨

对影响热作模具钢RH13质量稳定性的因素进行了较为深入的分析和探讨，并在此基础上提出了相应的改进措施。     

稀土元素在H13热作模具钢表面强化中的应用综述

综述了稀土元素在H13热作模具钢表面强化中的应用,重点探讨了在扩散渗入、离子注入及气相沉积等三种表面强化技术中的强化效果和作用机理.扩散渗入中,稀土元素主要起到催渗和微合金化的作用;离子注入中,添加稀土元素能形成致密的氧化物,可提高模具的抗高温氧化能力;气相沉积中,稀土元素的加入增强涂层的膜-基结合强度.结果表明,稀土元素的加入均能显著提高模具的使用寿命.