美标H13热作模具钢的锻造研发

介绍了莱钢美标H13热作模具钢的锻造生产工艺,控制好加热、锻造和锻后热处理,根据钢锭冶炼方式确定了简单可行的锻造工艺,降低锻造成本,生产出合格的锻件毛坯。     

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。     

H13热作模具钢热处理工艺研究

以热作模具钢的代表——H13热作模具钢的使用条件作为热处理工艺设定参数的主要考虑对象,采用合金化的角度简述合金元素在工件当中的作用,并分析现阶段H13热作模具钢的热处理过程中正火、球化退火、淬火、回火等工艺,以此为出发点,制定并完善了传统的热作模具钢的热处理工艺.     

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.     

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.     

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～…     

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，     

热作模具钢热处理工艺研究

本文以热作模具钢H13为主要研究对象,从其使用条件出发,简述了合金元素在工件当中的作用,并详细阐述了热处理工艺的控制要点。认为,正火应采用高温空冷正火,用以消除大部分碳化物;球化退火应采用等温球化退火,均匀冷却工件,减少其变形和开裂的倾向;淬火应采用1 010℃左右的高温淬火,以获得足够的晶粒度,保证工件的热强性;回火应在600℃左右回火三次较为适合。     

热作模具钢H13的非金属夹杂物研究

 通过对EAF－LF－VD－MC－ESR工艺生产模具钢H13各工艺环节系统取样,采用多种分析方法分析夹杂物的形貌、尺寸、数量及组成,系统研究了H13钢生产过程中夹杂物演变规律,同时对模具钢中TiN和VC夹杂物的析出进行了理论分析,并提出了生产过程中控制TiN和VC夹杂物析出的措施。     

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.     

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.     

Carbide Evolution in High Molybdenum Nb-microalloyed H13 Steel during Annealing Process

Based on the Thermo-Calc thermodynamic software,the type of equilibrium precipitated carbides and their contents in high Mo Nb-microalloyed H13steel(NMH13steel)were calculated.The composition,morphology,and distribution of carbides after spheroidal annealing of two forged experimental steels were comparatively examined by means of optical microscopy(OM),scanning electron microscopy(SEM),electron dispersive spectroscopy(EDS)and transmission electron microscopy(TEM).VC,M23C6 and M6C are identified in H13 steel after spheroidizing annealing,while(V,Nb)C,M23C6,M2C and M6C are observed in NMH13 steel.Moreover,it is found that the addition of Nb significantly enhances the stability of MC phase and the high Mo content accelerates the precipitation of small rod-shape M2C phase in NMH13 steel.The amount of the fine carbides in NMH13 steel obviously increased with M2C and M6C precipitated from the ferrite phase,which is in accordance with the results of thermodynamic calculations.     

热加工工艺对铝合金热模锻锻模寿命的影响

分析研究了冶炼、锻造及热处理等锻模热加工的各工序对锻模使用寿命的影响，并制定了预防锻模早期失效和提高锻模使用寿命的措施。     

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。     

电渣重熔H13钢中一次碳化物形成机制

 H13热作模具钢在电渣重熔过程中会在凝固末端形成粗大的碳化物及氮化物,由于生成温度高,热稳定性好,会保留到最终热处理状态,对钢材的性能产生严重影响。应用偏析模型计算并说明了凝固过程生成粗大的共晶碳化物和氮化物的可能,当固相率达到0.82时由残余液相生成TiN,随着温度进一步下降在接近凝固终点时生成VC0.88,由于碳化物中固溶了其他合金元素,认为生成的VC0.88的活度不为1,试验检测的碳化物合金元素含量与理论假设基本吻合。对粗大的碳氮化物的特点及细化减少碳化物进行简单讨论。     

H13改进型热作模具钢的组织与性能

 研究了高锰型马氏体热作模具钢SDH3-Mod的室温冲击韧性、回火稳定性和热疲劳性能,并结合透射电镜(TEM)分析了锰对其微观组织的影响。结果表明：SDH3-Mod钢回火组织中残余奥氏体以薄膜状存在于马氏体板条间,提高冲击韧性,延缓裂纹扩展;同时,锰在高温时阻碍碳化物粗化长大和延迟基体的回复再结晶,提高抗回火软化能力和热疲劳性能,使SDH3-Mod性能优于H13。     

莱钢H13模具钢的研究开发

介绍了莱钢研究开发高品质H13热作模具钢的过程，采用电炉→LF、VD精炼→钢锭→电渣重熔→锻造工艺生产的H13钢在做了大量检验分析后，质量性能优良。