低碳高硫磷钢硫化物凝固析出的热力学分析

以低碳高硫磷钢为研究对象,应用Schiel凝固方程对凝固过程中硫化物的析出进行了热力学模拟,分析了硫化物凝固析出的热力学规律及其影响因素.指出合理的锰、硫成分设计、采用连铸工艺和对钢液进行适当的钙处理,可以获得理想的硫化物形态及分布,为易切削钢的设计和应用提供了热力学依据.     

Thermodynamic Evaluation of Inclusions Formation and Behaviour in Steels during Casting and Solidification

For demanding applications high steel cleanliness and strictly controlled inclusions are required. Primary inclusions are formed during steel treatments in the ladle. Most of these are removed to the ladle slag or on the lining. However, the rest of the inclusions still remain through the successive process stages, and additionally new inclusions are formed during casting and solidification due to decreasing thermodynamic solubility of oxygen in the steel at lower temperatures, reactions with surrounding slag, refractory materials and eventual contact with air. Inclusions formation and transformation are simulated by thermodynamic calculations in the steel/inclusions/slag system taking into account the solidification phenomena. In this paper inclusions in Si/Mn‐deoxidised steel and Al‐deoxidised Ca‐treated steels are contributed. Calculations are compared with experimental results from steel plants.     

MnS在Ti-Al复合脱氧氧化物上的析出研究

采用高温电阻炉,通过改变不同冷却条件和不同硫含量,系统研究了Ti-Al复合脱氧夹杂对MnS夹杂物析出量和形貌的影响。试验结果表明:冷却速率对MnS的析出有着重要的影响。当钢液中硫的质量分数从0.001%增加到0.01%时,在炉冷条件下,MnS析出量随着钢液中硫含量的增加而增加。但是在水冷条件下,MnS的析出量不随钢液中硫含量的增加而变化。当钢液中w([S])0.008%时,所有氧化物夹杂表面都会析出MnS夹杂;当0.002%≤w([S])0.008%时,复合氧化物夹杂中MnO+SiO2含量越高,MnS越容易在氧化物上面析出。复合夹杂物中Ti3O5和Al2O3对MnS的析出没有明显影响。当w([S])0.002%时,基本没有MnS夹杂析出。MnS在低熔点氧化物上呈镶嵌状析出,在高熔点上呈包裹状析出。     

Two-Sublattice Thermodynamic Model on Carbonitride Precipitation in Microalloyed Steels Bearing Nb-V-Ti

Based on the two sublattice model of the regular solution,one being metal atom sublattice and another being interstitial atom sublattice,a thermodynamic model for the precipitates of niobium carbonitride,vanadium carbonitride and titanium carbonitride was established to study the starting-temperature of precipitates and the austenite compositions at given temperature in a low carbon steel.The calculation results show that starting-temperature of the precipitation of niobium carbonitride,vanadium carbonitride and titanium carbonitride are 1100℃,920℃ and 1340℃,respectively,the mole fraction of carbonitride precipitates is 8.65×10-4 in the 0.053C-0.0028N-1.28Mn-0.008S-0.031Al-0.046Nb-0.008Ti0.029V-Fe steel.When the N content is from 0.0028% to 0.0056%,the starting-temperature of the precipitation of the titanium carbonitride changes from 1340℃ to 1430℃.And the C content is from 0.053% to 0.07%,the startingtemperature of the precipitation of the titanium carbonitride hardly changes,but the atomic fraction of niobium in the carbonitride obviously increases.     

GCr15轴承钢凝固过程组分变化对夹杂物析出的热力学研究

基于Fact Sage热力学软件的最小吉布斯自由能原理,研究了不同[Ca]、[Mg]、[Al]、[O]含量条件下GCr15轴承钢凝固过程中夹杂物的析出行为。结果表明:随着[Ca]含量由0.000 5%增加至0.004 5%,轴承钢中析出的夹杂物类型由Ca O·2Mg O·8Al_2O_3、Ca O·2Al_2O_3向2Ca O·Si O_2、Ca S转变,钢中夹杂物总质量分数由约0.004 5%增加到约0.009 4%。随着[Mg]含量从0.000 1%增加到0.000 9%,钢中析出的夹杂物由Ca O·Al_2O_3、2Ca O·Si O_2向Mg O·Al_2O_3和Ca S转变,钢中夹杂物总质量分数由约0.003 2%增加到约0.004 1%;[Al]含量由0.005%增加至0.05%时,钢中析出的夹杂物类型由2Ca O·Si O_2向Ca O·Al_2O_3、Ca O·2Al_2O_3转变,夹杂物总量由0.002 8%增加至0.003 3%,变化相对不明显;随着[O]含量由0.000 3%增加至0.002 1%,钢中析出的夹杂物类型由Ca S向Ca O·Al_2O_3、Ca O·2Al_2O_3转变,夹杂物析出量由0.002 4%增加到约0.005 1%。     

Investigation on Inclusions in Non-oriented Silicon Steels

Metallurgical and Materials Transactions B - Inclusions in non-oriented electrical steels were automatically measured using Explorer 4 and extracted with a non-aqueous solution electrolytic method...     

合金元素影响高速钢中MC碳化物析出温度的热力学计算

高速钢中初生ＭＣ碳化物从液相中的析出温度是决定初生ＭＣ碳化物尺寸的主要因素。本文采用冶金热力学估算了合金元素Ｓｉ、Ａｌ、Ｗ、Ｍｏ等对初生ＭＣ碳化物析出温度的影响，提出了相应的计算机程序。结果表明，Ｓｉ和Ａｌ提高通用高速钢中ＭＣ碳化物的析出温度，而Ｗ、Ｍｏ等对ＭＣ碳化物析出温度影响不大。理论估算和实验结果相吻合。     

Formation and Deformation Mechanism of Al2O3-CaS Inclusions in Ca-Treated Non-Oriented Electrical Steels

Metallurgical and Materials Transactions B - Industrial trials were performed to study the effect of calcium treatment on inclusions in non-oriented electrical steels. The evolution and...     

Deformability of Oxide Inclusions in Tire Cord Steels

Metallurgical and Materials Transactions B - The deformation of oxide inclusions in tire cord steels during hot rolling was analyzed, and the factors influencing their deformability at high and low...     

Investigation of RE-O-S-As Inclusions in High Carbon Steels

The formation of RE-O-S-As inclusions is an inevitable issue when rare earth (RE) elements are used to modify the existing state of residual element arsenic. The evolution process of La-O-S-As inclusions in high carbon steels was investigated under conditions of different La contents. An in-situ sample preparation method was used to prepare film samples. The results show that it is practical to add RE elements to stabilize arsenic by generating As-bearing RE inclusions. A new type of As-bearing RE inclusion was discovered and identified as LaAsO₄. As La content increased from 0.003 to 0.089 wt pct, the dominant inclusions of the La-O-S-As system changed from La₂O₃ to La₂O₂S, then to La₂O₂S-LaAsO₄, and finally to LaAsO₄. A full model of the inclusion formation of the RE-O-S-As system was also established to describe what kind of inclusion to form in conditions of different atomic ratios of RE/O and RE/S. The first As-bearing RE inclusion is RE-O-As or RE-S-As, and RE-O-S-As inclusions can be controlled to form certain inclusions that make O and S useful to modify the existing state of arsenic.     

用白钨矿、氧化钼和钒渣冶炼合金钢的热力学分析

运用热力学状态图、化学反应等温方程式及活度对利用白钨矿、氧化钼和钒渣冶炼合金钢的热力学过程进行了计算和分析。结果表明：炼钢过程中,［Ｃ］、［Ｓｉ］和［Ａｌ］等都能将白钨矿、氧化钼和钒渣还原;而白钨矿、氧化钼和钒渣的回收率取决于炉渣碱度和氧化性、炼钢温度、反应气氛以及钢液中各元素的含量     

电渣重熔与连铸轴承钢中的夹杂物

研究了电渣重熔前后钢中氧及夹杂物的变化,结果表明:用电渣重熔工艺生产轴承钢,虽然氧含量比连铸钢高,但其大颗粒夹杂物数量少,尺寸较小,分布均匀,因此疲劳寿命高.     

A Coupled Thermodynamic Model for Prediction of Inclusions Precipitation during Solidification of Heat-resistant Steel Containing Cerium

A coupled thermodynamic model of inclusions precipitation both in liquid and solid phase and microsegregation of solute elements during solidification of heat-resistant steel containing cerium was established.Then the model was validated by the SEM analysis of the industrial products.The type and amount of inclusions in solidification structure of 253 MA heat-resistant steel were predicted by the model,and the valuable results for the inclusions controlling in 253 MA steel were obtained.When the cerium addition increases,the types of inclusions transform from SiO2 and MnS to Ce2O3 and Ce2O2S in 253 MA steel and the precipitation temperature of SiO2 and MnS decreases.The inclusions CeS and CeN convert to Ce2O3 and Ce2O2S as the oxygen content increases and Ce2O3 and CeN convert to Ce2O2 S,Ce3S4,and MnS as the sulfur content increases.The formation temperature of SiO2 increases when the oxygen content increases and the MnS precipitation temperature increases when the sulfur content increases.There is only a small quantity of inclusions containing cerium in 253 MA steel with high cleanliness,i.e.,low oxygen and sulfur contents.By contrast,a mass of SiO2,MnS and Ce2O2 S are formed in steel when the oxygen and sulfur contents are high enough.The condition that MnS precipitates in 253 MA steel is 1.2 w[O]+w[S]0.01%and SiO2 precipitates when 2 w[O]+w[S]0.017%(w[S]0.005%)and w[O]0.006%(w[S]0.005%).     

稀土2Cr13不锈钢中夹杂物的热力学分析及试验研究

采用金相、扫描电镜和能谱等分析手段,研究了微量稀土元素Ce对2Cr13不锈钢中夹杂物的变质作用,并对稀土夹杂物的形成进行了热力学分析和计算。研究结果表明:稀土元素Ce能有效地变质夹杂物Al2O3和MnS,其变质产物主要为球形的Ce2O2S和CeS。     

等离子体光谱仪定量分析低合金钢中稳定氧化夹杂物

钢中非金属夹杂物对钢的力学性能和工艺性能的影响,主要是降低材料的塑性、韧性和疲劳性能,尤其当夹杂物以不利的形状及分布特征存在时,对材料机械性能的影响更为严重。以往氧化夹杂物分量测定采用化学法和原子吸收法,测定周期长,且Ca、Cr、Mn、Fe等元素的氧化物含量很低,化学法测定有一定局限性。而采用等离子体光谱分析(ICP-AES)定量测定氧化夹杂物,由于夹杂物含量低,相对干扰少,此法具有速度快,灵敏度高,并可同时测定多元素等特点,从而大大缩短了分析周期,降低了分析成本和劳动强度。