固溶处理和时效对17-4PH沉淀硬化不锈钢组织性能的影响

试验得出O．053C-16．0Cr-4．5Ni-3．1Cu(17-4PH)沉淀硬化不锈钢1040℃1h油冷，固溶处理，470～490℃时效2h的组织和性能最佳，硬度可达HRC50。     

增材制造17-4PH马氏体不锈钢研究进展

17-4PH马氏体不锈钢具有高强高韧以及耐腐蚀等优异性能,在航空航天、核能和民用工业等领域得到广泛的应用。增材制造技术通过离散堆积的制备方法,能够实现复杂异形零部件的成形,满足装备迭代的需求。综述了国内外增材制造17-4PH的研究成果,针对增材制造微小熔池、快速熔凝、复杂热历史冶金特点,介绍影响增材制造17-4PH试样致密度的因素,阐述其相构成、微观组织和力学性能,简述后处理对17-4PH力学性能的影响规律,最后对增材制造17-4PH的发展进行展望。     

高温时效对铁素体不锈钢组织和性能的影响

通过金相、SEM和EDS等技术,研究了900 ℃下不同时效时间对超纯铁素体不锈钢组织和性能的影响。结果表明,439钢种高温时效对Ti(C,N)析出作用较小,晶界析出相TiN较少,晶粒粗化严重,塑性较低;441钢种高温时效会沿着晶界析出Fe2Nb(Laves)相,析出数量较多,晶粒较细小,但由于Fe2Nb(Laves)相沿晶界呈网状分布,对材料塑性影响较大;444钢种高温时效会在晶界和晶内析出Fe3(Nb,Mo)3C,析出数量较少,第二相钉扎作用较弱,部分晶粒出现异常长大,由于Fe3(Nb,Mo)3C析出相未呈网状分布,断后伸长率高于441钢种。     

17-4PH马氏体沉淀硬化不锈钢表面防护技术研究进展

17-4PH马氏体沉淀硬化不锈钢具有良好抗衰减性能、抗腐蚀和抗空蚀性能以及优异的力学性能,在核能、海洋和航天等工业领域有广泛应用。由于长期服役于高温、腐蚀、冲击和摩擦的复杂环境中,17-4PH零部件表面受到水蚀、空蚀、腐蚀和摩擦磨损等严重破坏,亟需开展针对性防护研究。为此综述了目前17-4PH不锈钢表面防护的研究进展,主要从表面强化、表面改性和表面涂敷3个角度分析其优缺点、应用现状,并对其未来发展趋势进行展望。     

17-4PH马氏体沉淀硬化不锈钢表面防护技术研究进展

17-4PH马氏体沉淀硬化不锈钢具有良好抗衰减性能、抗腐蚀和抗空蚀性能以及优异的力学性能,在核能、海洋和航天等工业领域有广泛应用。由于长期服役于高温、腐蚀、冲击和摩擦的复杂环境中,17-4PH零部件表面受到水蚀、空蚀、腐蚀和摩擦磨损等严重破坏,亟需开展针对性防护研究。为此综述了目前17-4PH不锈钢表面防护的研究进展,主要从表面强化、表面改性和表面涂敷3个角度分析其优缺点、应用现状,并对其未来发展趋势进行展望。     

17-4PH的时效动力学研究

全面研究了时效温度和时效时间对17-4PH不锈钢时效硬化过程的影响，用X衍射分析了硬化机制。结果表明，Cu的析出是其硬化的原因。时效温度越高，硬度上升越快；在460℃及其以下的温度时效5小时也未见硬化峰；高于460℃的时效会出现硬化峰，温度越高，硬化峰出现的时间越早，过时效会导致软化，温度越高，软化的速度越快。     

沉淀硬化不锈钢17—4PH中δ—铁素体含量的控制

研究了１７－４ＰＨ沉淀硬化不锈钢中δ－铁素体的形成因素，形态特征和化学成分配比，得出最佳成分（％）为：Ｃ ０．０３０￣０．０４５，Ｃｒ１５．８￣１６．４，Ｎｉ４．１０￣４．５０，Ｔｉ，Ａｌ，Ｎ≤０．０５，最佳固溶处理温度为１０５０℃。     

17-4PH沉淀硬化不锈钢的组织和性能研究

采用正交设计和方差分析法对１７－４ＰＨ沉淀硬化不锈钢的组织、性能进行了系统研究。研究结果表明,采用正交设计、方差分析是确定多因素热处理工艺快速有效的方法;对时效的１７－４ＰＨ钢再加热,可改交其时效组织,获得更好地韧性和耐蚀性。     

Effects of the Process Parameters on the Microstructure and Properties of Nitrided 17-4PH Stainless Steel

The effects of process parameters on the microstructure, microhardness, and dry-sliding wear behavior of plasma nitrided 17-4PH stainless steel were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and wear testing. The results show that a wear-resistant nitrided layer was formed on the surface of direct current plasma nitrided 17-4PH martensitic stainless steel. The microstructure and thickness of the nitrided layer is dependent on the treatment temperature rather than process pressure. XRD indicated that a single α _N phase was formed during nitriding at 623 K (350 °C). When the temperature increased, the α _N phase disappeared and CrN transformed in the nitrided layer. The hardness measurement demonstrated that the hardness of the stainless substrate steel increased from 320 HV_0.1 in the untreated condition increasing to about 1275HV_0.1 after nitriding 623 K (350 °C)/600 pa/4 hours. The extremely high values of the microhardness achieved by the great misfit-induced stress fields associated with the plenty of dislocation group and stacking fault. Dry-sliding wear resistance was improved by DC plasma nitriding. The best wear-resistance performance of a nitrided sample was obtained after nitriding at 673 K (350 °C), when the single α _N-phase was produced and there were no CrN precipitates in the nitrided layer.     

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...     

固溶处理对新型马氏体时效不锈钢力学性能的影响

研究了固溶处理对新型Cr-Ni-Co-Mo马氏体时效不锈钢力学性能的影响.结果表明,在低于1050 ℃固溶处理时钢中存在一些以χ相为主的金属间相,它们不仅严重破坏了钢的韧性,而且使钢在时效处理后的最终强度降低了100 MPa;经1050 ℃固溶处理后钢的基体组织为高密度位错的板条马氏体,此固溶态组织经适当时效处理可以使钢的强度达到1940 MPa,且得到与其高韧性匹配良好的综合力学性能.     

热处理工艺对15-5PH沉淀硬化不锈钢的力学性能与耐蚀性的影响

 研究了热处理工艺对15-5PH沉淀硬化不锈钢力学性能与耐蚀性的影响,并观察了钢中的强化相。结果表明,随着时效温度的升高和保温时间的延长钢的强度逐渐下降,塑性及冲击吸收功逐渐升高,这是由于逆转变奥氏体体积分数随温度升高而增加所造成的;随着时效温度升高钢的耐点腐蚀性能逐渐下降,在580和600 ℃时耐蚀性最差,在480 ℃时效钢的耐点腐蚀性能最佳且具有最高的强度,钢中主要的强化相是具有面心立方结构的富铜相。     

Tensile Mechanical Behavior and Spall Response of a Selective Laser Melted 17-4 PH Stainless Steel

The tensile mechanical behavior and spall response of a selective laser melted (SLM) 17-4 precipitation-hardening (PH) stainless steel were studied comprehensively through tensile test, plate impact experiment and microstructure characterization in the present study. The results reveal a steel with significant strain rate dependence on the tensile mechanical behavior and spall response. As the strain rate increases, the tensile yield stress increases, but there is no monotonic variation trend for the peak stress; grain structure remains unchanged first and then becomes fine; high-angle grain boundaries (HAGBs) increase; the martensite phase decreases at first and then increases. There is a close correlation among impact velocity, strain rate, peak stress, Hugoniot elastic limit (HEL) and spall strength. Strain rate, peak stress and HEL increase, while spall strength remains almost constant with the increase of impact velocity. As impact velocity increases, grain structure becomes fine, HAGBs increase and the martensite phase increases. The significant phase transformation is responsible for the tensile mechanical behavior and spall response, and the temperature rise was calculated to analyze its effect on phase transformation. Whether the preferred orientations are along the building direction or tensile direction is dependent on strain rate. Tensile and spallation specimens exhibit the ductile fracture mode and the damage originates from voids. It is interesting that the voids always tend to nucleate at melt pool boundaries. A spall damage evolution model is illustrated to describe the damage process.

     

海洋大气环境下17-7PH不锈钢的接触腐蚀研究

 为了研究17-7PH不锈钢在海洋大气环境下接触腐蚀的防护问题,将不同表面状态的17-7PH不锈钢板状试样在青岛团岛和海南万宁进行1年的大气暴晒试验,对其宏观腐蚀形貌对比,并测定其疲劳寿命,采用扫描电子显微镜(SEM)观察暴晒试样表面腐蚀形貌,用光学显微镜比较腐蚀坑深度,分析海洋大气腐蚀对17-7PH不锈钢疲劳性能的影响,最后得出了17-7PH不锈钢的腐蚀防护措施。结果表明：在青岛暴晒的不涂漆17-7PH不锈钢试样表面色泽变暗,有均匀的细小点蚀,而海南的试样表面有大面积较均匀的褐色锈层,特别是17-7PH不锈钢与TC18钛合金连接处腐蚀较为集中,但腐蚀并没有降低其疲劳寿命;从暴晒试样的表面微观腐蚀形貌比较,无论涂漆与否,17-7PH不锈钢表面都有轻微腐蚀,但只局限于表层,点蚀不深,并且趋向均匀腐蚀;17-7PH不锈钢抗大气腐蚀性能很好,经钝化后可不涂漆直接在海洋大气环境中使用1年,而不会对其疲劳性能产生明显影响。     

热处理对铁素体不锈钢组织和性能的影响

研究了不同热处理工艺对铁素体不锈钢的组织与性能的影响.结果表明 铁素体不锈钢固溶处理时,温度在900 ℃以下组织无明显变化,其硬度随着温度的上升变化缓慢;900 ℃左右发生再结晶,硬度显著降低;在475 ℃热处理后析出物增多,硬度增加,耐腐蚀性能严重下降,即有明显475 ℃脆性现象.