Fe-0.8C-0.4N三元合金淬火马氏体表征

08F钢薄片(厚0.25 mm)经700℃~720℃盐浴碳氮共渗3 h后直接水冷,其扩散层为均匀的Fe-0.8C-0.4N合金。应用X射线衍射仪、扫描电子显微镜和透射电子显微镜等对Fe-0.8C-0.4N合金的显微组织结构表征。结果表明,淬火组织中同时存在块状残余奥氏体、隐晶马氏体和沿原奥氏体晶界分布的珠光体/贝氏体组织。Fe-0.8C-0.4N马氏体组织主要形态为细小板条状,且在板条内部存在许多斜贯穿板条的孪晶,这些孪晶可分为平直型微孪晶或者弯曲型孪晶。Fe-0.8C-0.4N马氏体与原奥氏体之间晶体学取向关系符合K-S关系。     

Study of bipolar pulsed nanocrystalline plasma electrolytic carbonitriding on nanostructure of compound layer for CP-Ti

Surface hardening of commercially pure titanium using bipolar pulsed nanocrystalline plasma electrolytic carbonitriding has been studied in this investigation. The coating process has been performed on triethanolamine-based electrolytes using a cooling bath. The nanostructure of obtained compound layers was examined with figure analysis of SEM nanographs. The effects of process variables (i.e., frequency, temperature of electrolytes, applied voltage, and treatment time) have been studied experimentally. Statistical methods were used to achieve the optimum size of nanocrystals. Finally, the contribution percentage of the effective factors of pulsed current was revealed, and confirmation showed the validity of obtained results. It has also been revealed that by changing the size of nanocrystalline carbonitrides, other properties of the coating will change significantly.     

无毒液体碳氮共渗剂的研制

氰化工艺有许多优点,但因需要使用剧毒原材料氰盐,所以氰化法已基本淘汰.将市售普通无毒原料处理后,与木炭粉等配制的渗剂用于液体碳氮共渗,其处理效果极佳.渗速与传统氰化法相当,但盐浴中渗剂的含量只需4%左右,比氰化法盐浴中氰盐的含量少得多(一般20~30%)而且此渗剂具有优良的稳定性,每添加一次(盐浴重量的2%左右)可连续使用3小时以上.     

高合金钢碳氮共渗氢致开裂的研究

研究了碳氮共渗时的氢脆及其消除方法 ,发现高合金钢氢脆敏感性大 ,在一般低温回火中很难消除 ,如淬火后经 15 0℃×3h回火 ,2 0Cr2Ni4A和 18CrNiWA钢的断面收缩率在碳氮共渗时分别为空气加热的 10 %及 6 4%。试验发现 18CrNiWA钢中氢的析出较 2 0Cr2Ni4A钢中的更难。提出了采用时效或在碳氮共渗后期通氮排氢的方法来氢脆     

手用钢锯条液体碳氮共渗工艺的研究

提出一种可再生液体碳氮共渗新工艺，已在锯条行业推广应用了３年，在锯条质量、工艺操作、新旧工艺衔接、降低成本、治理环境污染等方面均获成功。目前新工艺在国内生产的锯条每年已达８．８亿支。生产使用证明：新工艺可取代传统氰化钠盐浴和尿素盐浴工艺，具有渗速快、硬度高、锯切性能好、节约能源、无有害气体排放、渗层均匀、碳氮浓度容易控制等优点。     

室温形变对20CrMnTi钢碳、氮共渗层抗磨损性能影响的研究

本文采用室温轧制形变量、碳一氮共渗温度、时间三因子二次旋转组合设计方法,着重研究了室温形变对20CrMnTi钢;碳、氮共渗层抗磨损性能的影响,并用微机进行数据的数学处理,推算出磨损失重量、室温形变量、共渗温度及时间关系的回归方程。结果表明:室温形变能明显提高共渗层的抗磨损性能,而且存在最佳形变量,对应最佳形变量磨损失重减小一半。本文还讨沦了适量室温形变改善和提高渗层抗磨损性能的原因。     

耐火材料成型模具的气体碳氮共渗

介绍了气体碳氮共渗技术的基本原理、基本过程和在耐火材料成型模具热处理中的应用,并分析了应用过程中可能出现的问题和解决措施。气体碳氮共渗工艺不但延长了耐火材料模具的使用寿命,而且降低了对环境的污染。虽然目前气体碳氮共渗技术的设备及其自动控制水平较高,但是关键阶段还需人工控制,因此,需要操作工人严格执行工艺规程,出现问题及时进行补救。     

电阻法测控炉气碳氮势数学模型的物理分析

电阻法测控炉气碳氮势数学模型的物理分析胡锐，杨思品，席守谋（西北工业大学）１前言用电阻法直接测控碳氮共渗过程中碳、氮势的研究，近年来有较大发展［１］．有研究表明，碳、氮原子在γ－Ｆｅ中扩散特性相似，在有碳参与的情况下，渗氮动力学几乎不受影响［２］，可...     

Study of bipolar pulsed plasma electrolytic carbonitriding on nanostructure of compound layer for a gamma Ti-Al alloy

The surface hardening of a gamma Ti-Al alloy by using bipolar pulsed nanocrystalline plasma electrolytic carbonitriding has been studied in this investigation. Coating process was performed on a triethanolaminebased electrolyte by a cooling bath. The nanostructure of the obtained compound layer was examined with the figure analysis of the scanning electron microscopy (SEM) nanographs. The effects of the process variables, i.e., frequency, temperature of the electrolyte, applied voltage and treatment time, have been experimentally studied. Statistical methods were used to achieve the optimum size of the nanocrystals. Finally, the contribution percentage of the effective factors of the pulsed current was revealed, and the confirmation run showed the validity of the obtained results.     

氨气流量对碳氮共渗炉气碳势的影响

分析了碳氮共渗时炉气碳势不稳定的原因，通过试验找出了碳势和氧电势之间的对应关系，并提出了碳势控制的方法。