20CrNiMo钢球化退火工艺研究

采用亚温球化退火、普通球化退火、等温球化退火对20CrNiMo钢进行热处理工艺试验,利用光学显微镜和布氏硬度计分别对球化后的显微组织进行观察和硬度检测。结果表明,20CrNiMo钢经过普通球化退火、等温球化退火、硬度值≤160HBW,且经过710℃亚温球化退火,随着时间的延长,球化率有所上升,当球化退火时间达25 h以上时,亚温球化退火能获得65%以上的珠光体球化率;采用750℃保温6 h后再以10℃/h的冷却速度缓慢冷却的普通球化退火工艺,能获得83%以上的珠光体球化率;采用750℃保温6 h,经30 min炉冷到650℃保温6 h的等温球化退火,能获得硬度值为145HBW和93%的球化率。     

6CrW2Si钢剪刃的强韧化处理

6CrW2Si 钢制冷剪刃,原最终热处理采用860～890℃油淬,然后根据硬度要求确定回火温度。长期以来,由于“堆刃”和“崩刃”,使这一产品处于使用寿命较低的水平(不如常州产品)。为此,通过各种奥氏体化温度对该钢强度、硬度、韧性及显微组织的影响的试验研究,得出了最佳奥氏体化温度(940～960℃)和适当的回火温度(350～370℃),使该钢获得了强韧化效果。按新工艺生产的6CrW2Si 钢冷剪刃,在鞍钢冷轧厂碎边剪上安装使用结果是:最高天数9天/刃,平均为7天/刃。而常州剪刃最高使用天数7天/刃,平均为5天/刃。这样,一举超过了常州剪刃的使用寿命。     

热作模具钢H13连轧材退火工艺研究

为满足用户对加工硬度的特殊需求(硬度≤220HBW),对热作模具钢H13连轧材进行了不同退火温度、保温时间和辊速下的退火试验,以确定最佳的退火工艺,并借助金相显微镜对最佳退火工艺下的H13退火态组织进行分析。结果表明:H13的退火硬度与退火温度、保温时间、辊速有关,退火温度越高、保温时间越长、辊速越慢,试样硬度越低。退火温度为840℃,保温时间为5~6h,辊速5.5m/h为最佳退火工艺,钢材平均硬度可以降到198HB左右,金相组织满足用户标准要求。     

回火温度对渗碳钢18Cr2Ni4WA组织和硬度的影响

为满足用户加工HBW硬度值≤269的需要,降低18Cr2Ni4WA钢Φ60 mm材硬度,利用连轧厂实际辊底式退火炉进行了630～750℃5h炉冷至500℃空冷的回火试验,并借助金相显微镜对18Cr2Ni4WA钢不同回火温度下的组织进行了分析,以确定最佳的回火温度。结果表明,18Cr2Ni4WA钢随回火温度的升高硬度先下降后上升,当温度为670℃时,钢材平均HBW硬度值最低(HBW238左右),回火组织为均匀的回火珠光体组织。     

轴承钢材在连续式退火炉中球化退火工艺试验

轴承钢材在带有保护气氛的辊底式钢材连续退火炉中,进行球化退火,可获得球化组织均匀细散,表面无氧化,脱炭轻微、硬度均匀一致的高质量退火材。本文总结了轴承钢在连续式退火炉中进行球化退火时,各种工艺参数对球化组织和硬度的影响。为改善炭化物的颗粒度和分散度,获得不同级别的球化组织和退火硬度,提供了可靠的球化退火工艺。     

大变形65Mn弹簧钢退火后的组织及性能研究

研究了球化退火处理对拉拔态65Mn弹簧钢的组织和性能的影响。实验将大变形的弹簧钢丝进行再结晶退火球化处理工艺,将碳化物球化,观察其组织并测其硬度。实验结果表明,一定的保温温度与时间内,随着退火温度的升高,球化效果较好,硬度逐渐降低;退火温度超过A1,将会形成片状珠光体,硬度会升高。     

退火处理对A6钢组织和性能的影响

通过研究不同退火工艺对A6钢组织和性能的影响,并选出2个最佳的球化退火工艺。结果表明:与传统常规退火工艺相比,最佳球化退火工艺有效地改善了钢材的球化组织和降低退火硬度,而且成倍地提高了钢材退火态的塑性和韧性,和较大幅度地提高了淬、回火态钢材的塑性和韧性。     

14.9级42CrMoVNb-NJ螺栓钢球化退火工艺研究

研究了球化退火工艺的奥氏体化温度、保温时间以及冷却速度对14.9级微合金42CrMoVNb钢球化退火的影响。通过改变球化过程炉冷的冷速、奥氏体化温度以及保温时间,并通过对各球化退火工艺后的组织和硬度进行观察、测定,结合冷镦实验研究42CrMoVNb螺栓钢中珠光体球化效果。结果表明:冷速较快时,珠光体球化效果不明显;工艺750℃x3h后降至710℃x6h再炉冷到500℃后空冷(降温速率均为15℃/h)的球化效果最好,硬度最低,且塑性满足冷镦试验要求。     

Nb对高碳钢珠光体球化的影响

设计了2种不同Nb含量的高碳珠光体钢(0.025Nb和Free-Nb),采用光学显微镜、扫描显微镜、透射电镜和硬度测试仪对两种试验钢珠光体球化前后的显微组织进行了观察和球化后的硬度进行了测量。结果表明:Nb元素可以细化高碳珠光体钢的片层间距,相同条件下具有更多的铁素体-渗碳体界面,在球化退火的第一阶段提供大量的位错和亚晶界使片状珠光体快速熔断,同时也给第二阶段碳的扩散提供高速扩散通道;细小的片层间距缩短了碳和合金元素的扩散距离,使球化转变速度加快,促进了高碳珠光体的球化。Nb元素的添加获得了细小片层间距以及更多的合金碳化物使试验钢的初始硬度偏高,球化退火前4 h硬度值下降幅度较大,球化退火4 h后对试验钢硬度的影响不大。     

退火温度和再结晶比例对0.58Si无取向硅钢0.50mm冷轧板性能的影响

无取向硅钢(/%:0.003C,0.58Si,0.20Mn,0.010P,0.002S,0.25Al,0.003 0N)0.5 mm冷轧薄板由2.6mm热轧板冷轧而成。研究了390~820℃退火再结晶组织比例对该钢磁性能、抗拉强度和硬度的影响。结果表明,未发生再结晶时(390~480℃退火),退火温度对抗拉强度和硬度的影响很小;当再结晶组织比例≥70%时(560~820℃退火),降低退火温度能够有效提高抗拉强度,同时不显著恶化磁性能,但对硬度没有影响;当再结晶组织比例70%时(480~560℃退火),降低退火温度使磁性能剧烈恶化,但能够大幅提高抗拉强度和硬度;当退火温度560℃,再结晶比例70%时无取向硅钢的性能为抗拉强度R_m 470 MPa,HV1硬度值140,铁损P_(1.5/50)7.5W/kg,磁极化强度J_(50)1.70 T,综合性能最佳。     

The Influence of Isothermal Semi‐solid Processing on Microstructure,Hardness and Young's Modulus of a Hypoeutectic Chromium Steel

Steel billets of the hypoeutectic chromium steel X210CrW12 (material number 1.2436, AISI D6) are reheated into the semi‐solid state and isothermally extruded using a ceramic extrusion tool at low process forces. Extruded bars show good microstructural as well as chemical homogeneity. Nanoindenter measurements of untreated and extruded samples prove that hardness and Young's modulus are increased after semi‐solid extrusion. Hardness values are retained after annealing, while Young's modulus drops back to the initial value of untreated X210CrW12. Results are consistent with metallurgical investigations on phase formation and mechanical properties of X210CrW12 processed in the semi‐solid state. Thus, the viability of isothermal processing and the underlying tool concept is demonstrated in terms of work piece quality. The suitability of X210CrW12 for semi‐solid processing and the potential improvement of mechanical properties are validated.     

精密车削用16MnCrS5钢棒材生产工艺优化

通过试验确定精密车削用16MnCrS5棒材的生产工艺,研究合适的硫含量、冷却速度和退火温度参数,满足高端汽车销轴精密车削零件要求。结果表明,试验的S含量0.028%～0.035%的16MnCrS5热轧棒材以1.37～1.69℃/s冷却速度冷却后,再采用连续退火炉进行620℃×6 h的去应力退火,可得到硬度满足180～215HBW的去应力退火精密车削用棒材。     

轧后穿水对20CrMnTiH组织和硬度影响的热模拟试验

 降低热轧棒材的硬度有利于下游用户的加工。试验利用热模拟试验机研究终轧温度、轧后穿水以及冷床冷速对小规格20CrMnTiH钢棒材的组织比例和硬度的影响。在轧后不穿水的情况下,终轧温度越低或者冷速越慢,轧材的铁素体体积分数越高,贝氏体体积分数越低,轧材的硬度也越低。轧后穿水能明显提高轧材的铁素体比例,降低贝氏体比例,从而大幅降低轧材的硬度。穿水轧材硬度小于217HBW,满足退火或高温回火材的硬度要求。     

退火温度对铁素体不锈钢Y0Cr17SiS组织和性能的影响

热轧状态下的铁素体不锈钢Y0Cr17SiS综合性能较差,不能满足加工使用要求,需进行退火处理,研究了退火温度750℃、800℃、850℃、900℃对Y0Cr17SiS钢Φ11 mm热轧材的组织和性能的影响.结果表明,经900℃2 h空冷退火,Y0Cr17SiS钢组织均匀、无析出物产生,抗拉强度为510 MPa,断后延伸...     

1Cr12Ni3Mo2VN退火工艺研究

通过1Cr12Ni3Mo2VN（KT5312AS6）钢不同的退火工艺、退火温度及时间、二次退火及退火冷却方式对硬度的影响实验研究,得出本钢种最佳退火工艺。经实验证明,采用不完全退火及二次退火方式,能够满足标准对交货硬度的要求。     

Thermal Stability of Cathodic Arc Vapour Deposited TiAlN/AlCrN and AlCrN/TiAlN Coatings on Tungsten Carbide Tool

TiAlN/AlCrN and AlCrN/TiAlN bilayer coatings were deposited on tungsten carbide cutting inserts using the plasma enhanced physical vapour deposition process. Their thermal stability was varied by annealing the specimens at different temperatures and time durations. The thermal stability was evaluated from hardness measurement, oxygen absorption and X-ray diffraction (XRD) patterns. TiAlN/AlCrN coating initially shows an increase in hardness, but it decreases when the annealing temperature is increased. A high hardness of 46 GPa is measured in the TiAlN/AlCrN coating annealed at 600 °C for 08 h. But, AlCrN/TiAlN coating displays a decrease in hardness after annealing at 600 °C, and the hardness increases to 47 GPa on increasing the annealing temperature further (1000 °C for 6 h). From weight measurements, it is clear that the TiAlN/AlCrN bilayer coating results in weight reduction initially, but it increases with a further increase in the annealing temperature. In contrast, in the AlCrN/TiAlN coating, the weight increases monotonically, but gradually, with increasing temperature of annealing. The XRD results are discussed with reference to the different oxide phases formed in the two bilayer coatings during annealing.     

固溶-时效处理对GH2696合金的组织及硬度的影响

研究了时效硬化型GH2696合金在不同热处理工艺下的微观组织演变及硬化行为。结果表明,随着固溶温度提高,GH2696合金基体的过饱和度增加。经1100 ℃ 2 h固溶的GH2696合金γ′相在780 ℃ 16 h时效处理时析出,导致硬度显著提高。650 ℃ 16 h低温时效处理起到补充时效硬化的作用,其HBW硬度值为350。     

Effect of silicon on the wear resistance of high-carbon steels with the structures of isothermal decomposition of austenite during friction and abrasive action

The hardness and wear resistance during sliding and abrasive friction of 80S2 (0.83% C, 1.66% Si) and U8 (0.83% C) steels subjected to the isothermal γ → α decomposition in the temperature range 330–650°C and additional 5-min annealing at 650°C are compared. The optimum decomposition temperature is found to be 550°C. At this temperature, fine lamellar pearlite with the maximum hardness and wear resistance as compared to other pearlitic and bainitic structures forms in the silicon steel. The silicon-alloyed fine lamellar pearlite of 80S2 steel is found to have high hardness and abrasive wear resistance as compared to the similar structure in plain U8 steel; however, this pearlite has no advantages in the wear resistance under conditions of sliding friction on a steel plate. Silicon alloying of the bainitic structures in the eutectoid steel leads to a noticeable decrease in the wear resistance during sliding friction and abrasive action. Friction oxidation is shown to negatively affect the abrasive wear resistance of the silicon steel.