冲击能量对 Fe-C-Mo-V 堆焊合金抗磨粒磨损性能的影响

采用含Fe-C-Mo-V的气体保护药芯焊丝堆焊制备磨损试样,并对其进行不同冲击能量下的动载冲击磨粒磨损试验. 通过扫描电子显微镜配合能谱分析、磨损失重测试和激光扫描共聚焦显微镜观察等测试方法,对熔敷金属的显微组织及磨痕特征进行分析及表征,研究了熔敷金属在不同冲击能量下的磨粒磨损行为. 结果表明,熔敷金属的显微组织主要由奥氏体基体、层片状共晶组织及团块状的VC硬质相构成. 熔敷金属的磨损失重、磨痕粗糙度以及磨痕深度均随冲击能量的增加而逐渐减小. 磨损机制为磨粒对奥氏体基体的微观切削以及塑性变形. 随着冲击能量的增加,熔敷金属产生加工硬化,磨痕亚表面出现形变马氏体组织,且VC硬质相与层片状共晶组织相互作用,共同提高堆焊层的硬度,从而提高基体的耐磨性,增强抗冲击性能.     

Fe-Cr-C耐磨堆焊合金磨粒磨损行为

采用埋弧堆焊方法,在Q235钢表面制备Fe-Cr-C耐磨合金,在MLS—225型湿式橡胶轮磨粒磨损试验机上进行磨粒磨损试验,通过对磨损试样表面的扫描电子显微镜观察分析并结合能谱成分分析研究磨损形成机制.结果表明,Fe-Cr-C耐磨堆焊合金在试验的湿石英砂磨料磨损条件下,磨损机制以微裂纹引起的剥落去除机制为主,也存在一定数量的犁沟或犁皱造成的微切削去除机制.剥落的发生与碳化物密切相关,能谱成分分析表明剥落坑内Cr元素含量对应在(Cr,Fe)7C3铬含量范围内,说明剥落坑是碳化物断裂造成的.     

合金元素对抗冲击磨损堆焊材料性能的影响

成功研制了一种适用丁抗冲击磨料磨损条件下的堆焊合金，合金系统为Fe—Mn—Cr—Mo—V，在受到较大载荷冲击后较焊态堆焊层硬度提高66％。因此陔堆焊合金的抗冲击磨料磨损性能和堆焊层金属的加工硬化效果都很优异。在保证堆焊层组织为奥氏体的前提下，系统地研究了合金元素Cr、Mo、V等多元复合强化提高抗磨料磨损的能力及其对堆焊层组织性能的影响规律。     

中铬奥氏体合金抗冲击磨损堆焊材料

针对高应力磨粒磨损工况条件研制的中铬Ｃ－Ｃｒ－Ｍｏ系奥氏体体堆焊材料ＦＡＷ焊条,具有焊接工艺性好,堆焊金属抗裂性好和加工硬化率高的特点,是替代奥氏体锰钢的理想焊接材料。通过对该材料的化和磨损性能及其机理的试验研究,探讨了合金的冷作硬化及冲击磨损的一般规律。硬化机制以形变强化与碳化物析出强化为主,磨损形式以塑性凿削式去除为主。     

抗冲击磨损堆焊合金的组织与性能

针对具有冲击磨粒磨损工况条件,成功研制出了一种奥氏体堆焊焊条EKCM50.该堆焊材料为Fe-Mn-Cr-Mo-V合金系,经过系统试验和现场应用,并与传统的高锰钢焊条对比,表明此种堆焊材料具有焊接工艺性好、堆焊金属加工硬化率高和耐凿削式冲击磨损性能优异的特点.通过对该材料的加工硬化和磨损性能的试验研究,探讨了此种奥氏体材料的加工硬化及耐磨机理,以及加入的合金元素对该焊接材料的耐磨性及耐磨机理的影响规律.     

抗冲击磨损奥氏体堆焊材料

针对具有冲击磨粒磨损工况条件，成功研制出了一种奥氏体堆焊材料EKCM50。该堆焊材料为Fe-Mn-Cr-Mo-V合金系，通过耐磨性对比试验分析，堆焊合金耐磨性能优于D256焊接材料。经过加工硬化冲击试验，EKCM50焊接材料堆焊层硬度由32HRC升高到45HRC，经过冲击磨损试验，40min后，试验材料堆焊磨损失重几乎不变。通过对该材料的加工硬化和磨损性能的试验研究，探讨了此种奥氏体材料的加工硬化及耐磨机理，以及加入的合金元素对该焊接材料的耐磨性及耐磨机理的影响规律。     

热处理对新型Fe-Cr-Mn-Co合金堆焊层磨粒磨损性能的影响

采用钨极氩弧焊(TIG)将新型Fe-Cr-Mn-Co合金堆焊在304不锈钢基体表面,对比研究热处理对堆焊合金磨粒磨损性能的影响。采用金相观察、硬度测量、失重分析和扫描电镜(SEM)对不同工艺热处理的堆焊合金金相组织、硬度、磨损性能及磨损机理进行了分析。研究结果表明:Fe-Cr-Mn-Co堆焊合金微观组织均为奥氏体,重熔和固溶处理能使晶粒细化、组织均匀,前者效果更佳;重熔后的堆焊合金硬度最高、耐磨性最好,但与固溶处理的相差不大,304不锈钢最差;合金的失效为凿削式磨粒磨损和塑性变形产生的疲劳破坏混合模式。     

Hank's模拟体液中医用TLM合金的微磨粒磨损行为

采用TE66微磨粒磨损实验机对外科植入材料Ti-Zr-Nb-Mo-Sn(TLM)钛合金在Hank's模拟人体体液中的微磨粒磨损行为进行研究。通过正交实验结果可知:影响TLM钛合金微磨粒磨损行为的各因素的显著程度由高到低依次为料浆浓度、载荷、滑移速度、磨粒及滑移距离,并研究料浆浓度对TLM钛合金微磨损行为的影响。结果表明:不同载荷下,由于单位体积内的磨粒数量增加致使TLM钛合金的磨损体积随料浆浓度增加而增加;摩擦因数在微磨损-腐蚀共同作用下随料浆浓度增加先增加而后降低,主要是由于随着微磨损-腐蚀的进行,在摩擦副表面产生氧化膜或钝化膜,而这些膜具有一定的润滑作用致使摩擦因数降低;同时可得知在浓度相同时,载荷越大,摩擦因数越大。     

铬含量对Fe-Cr-B堆焊合金显微组织及耐磨性的影响

目的在Fe-x Cr-3.5B-0.1C药芯焊丝中加入不同含量的铬,了解铬含量对堆焊合金硼化物形貌以及耐磨性能的影响。方法采用CO_2气体保护堆焊的方法在Q235钢基板上制备Fe-Cr-B系耐磨合金,利用光学显微镜、XRD、SEM等方法观察堆焊合金层的显微组织结构,以及湿砂橡胶轮磨粒磨损试验机对堆焊层进行磨粒磨损试验。结果堆焊合金层主要由铁素体枝晶、马氏体、珠光体和硼化物组成,硼化物随着Cr含量的增加发生Fe_2B到M_2B(M=Fe,Cr)的转变,它主要分布在金属基体的连续网状和鱼骨状结构中。凝固过程中,当Cr质量分数大于9%时,首先形成初生M_2B颗粒,随后形成共晶的M_2B和BCC结构的Fe基固溶体,这种共晶的微观结构主要由基体和长条状的M_2B硼化物组成。从Cr与(Fe,Cr)的原子数分数比值可以看出,硼化物发生从Fe_2B→(Fe,Cr)_2B→(Cr,Fe)_2B的转变。铬含量对Fe-Cr-B系耐磨堆焊合金的组织、硼化物形貌有较大影响。由于硼化物空间结构的变化,硼化物的显微硬度会随着铬原子进入Fe_2B而逐渐提高。结论随Cr含量的增加,及共晶硼化物硬质相的析出,堆焊合金的硬度和耐磨性呈现持续提高的趋势。当Cr含量为20%时,合金中生成的长条状M_2B相作为耐磨骨架无序的分布且镶嵌于基体中,合金耐磨料的磨损性能比Cr含量为9%时的提高了约7.4倍。     

耐磨堆焊材料的研制

在冲击磨料磨损工况条件下工作的工件磨损十分严重,直接导致了生产成本增加,为企业增添了很大的负担.针对该种磨损工况,通过系统试验成功研制出一种抗冲击磨料磨损堆焊焊条.该堆焊焊条为Fe-Mn-Cr-Mo-V合金系,经过实验室试验和现场应用,表明此种堆焊焊条具有焊接工艺性好、堆焊金属加工硬化率高和耐凿削式冲击磨损性能优异的特点.此外,通过对该材料的加工硬化和耐磨性能及其机理的试验研究,探讨了此种堆焊焊条的加工硬化及耐磨机理.     

Influence of material characteristics on the abrasive wear response of some hardfacing alloys

This study examines the abrasive wear behavior of two iron-base hardfacing materials with different combinations of carbon and chromium after deposition on a steel substrate. Effects of applied load and sliding distance on the wear behavior of the specimens were studied. Operating material removal mechanisms also were analyzed through the scanning electron microscopy (SEM) examination of typical wear surfaces, subsurface regions, and debris particles. The results suggest a significant improvement in the wear resistance of the hardfaced layers over that of the substrate. Further, the specimens overlaid with the material with low carbon and high chromium contents attained better wear resistance than the one consisting of more carbon but less chromium. The former specimens also attained superior hardness. Smoother abrasion grooves on the wear surfaces and finer debris formation during the abrasion of the hardfaced samples were consistent with wear resistance superior to that of the substrate.     

B元素对Fe-Cr-C系耐磨堆焊合金组织和耐磨性的影响

采用直径为1.6 mm的细径药芯焊丝,利用CO₂气体保护焊堆焊的方法制备了含有1.0%~3.0%C(质量分数),15%~20%Cr,0%~2.0%B的高铬堆焊合金.研究了B₄C含量对堆焊合金的硬度及耐磨性的影响.结果表明,堆焊合金的硬度从57.1 HRC增加到65.2 HRC,硬度提高14.2%;堆焊层合金的相对耐磨性从3.5倍提高到18.0倍.借助光学显微镜、扫描电镜和X射线衍射等微观分析方法,研究了堆焊合金的显微组织及碳化物分布形貌.结果表明,堆焊合金的显微组织主要由铁素体+奥氏体+(Fe,Cr)₇C₃组成,加入B₄C可显著改善堆焊合金层基体组织,使碳化物(Fe,Cr)₇C₃数量增加且呈弥散分布.     

A comparison of material removal mechanism under low stress abrasive condition of steel and hardfacing alloys

The low stress abrasive wear behavior of two types of steels commonly used for making a number of commonly used engineering components has been compared with the composition of a few hardfacing alloys that can be overlayed on the steels to impart a wear-resistant surface. The mechanism of material removal as studied by the scanning electron micrographs of the worn and transverse sections is different for the steels and hardfacing alloys. An attempt has been made to explain the mechanism of material removal for the steels and hardfacing alloys.     

Effect of microstructure and chemical composition of hardfacing alloy on abrasive wear behavior

Hardfacing, a surface modification technique, is used to rebuild the surface of a workpiece. The economic success of the process depends on selective application of hardfacing material and its chemical composition for a particular application. In this context, three hardfacing electrodes having different chemical compositions have been selected and their abrasive wear responses was compared with that of mild steel. The emphasis has been made to realize the effect of microstructure and chemical composition on the wear response of the hardfacing material with respect to mild steel. It has been observed that the wear rate of hardfacing alloys is lower than that of mild steel. The hardfacing alloy having the highest chromium content exhibits the lowest wear rate.     

High stress abrasive wear behavior of some hardfaced surfaces produced by thermal spraying

Steel surfaces were thermally sprayed with nickel chromium boron (NCB) powder (with and without tungsten carbide) using an oxy-acetylene torch. The sprayed (hard) surfaces and substrate were characterized for abrasive wear properties. Test parameters such as load and sliding distance were varied. A significant improvement in the abrasive wear resistance (inverse of wear rate) was noted for the thermally sprayed surfaces as compared to that of the substrate. Wear surfaces, subsurface regions, and debris were examined in order to ascertain the operating wear mechanisms. Substrate (mild steel), because of its low hardness, suffered severe wear through the cutting, ploughing, and wedging action of the hard abrasive (silicon carbide). Deep cuts on the worn surface, a bulky transfer layer, subsurface cracks, and large-size debris were observed. However, wear was reduced due to high hardness of the layer of NCB powder on the substrate, which resisted the penetration of abrasive into the surface. Presence of tungsten carbide in the layer of NCB powder further reduced the wear of the corresponding specimen because of very high hardness of the tungsten carbide. Shallow wear grooves and finer debris were observed for the NCB coating with and without tungsten carbide. Cutting was the predominating wear mechanism in the case of coatings.     

硼化物强化铁基堆焊合金显微组织与耐磨性

为了提高在严峻工况条件下工作的机械零件的耐磨性,采用等离子弧堆焊技术,制备硼化物强化铁基堆焊合金。借助OM,SEM和XRD等分析手段对合金组织和硼化物相形貌进行分析,并与未加入硼的Fe-Cr-C的堆焊合金进行对比。结果表明:堆焊合金中加入w(B)4.5%可改变基体的组织组成及硼化物的数量和分布形态,从而改善耐磨性。硼化物由大量菊花状M23(C,B)6和少量块状M7(C,B)3相组成,BC4与Cr2B的数量较少。耐磨粒磨损试验结果表明:堆焊合金的耐磨性随着硼含量的增加而先增大后下降,加入w(B)4.5%的堆焊层中形成的大量高硬度硼化物分布在具有较高强韧性的马氏体和奥氏体基体上,使其具有最佳的耐磨性,其磨损量仅为未加入硼时的1/6。     

钒对铁基碳化钨耐磨堆焊层组织和性能的影响

在自研制的碳化钨管状药芯焊条中添加不同含量的钒元素（0%~3%）并制备堆焊合金,通过SEM,XRD,EDS等研究分析手段,研究不同钒含量对碳化钨耐磨层组织性能的影响规律.结果表明,钒含量与堆焊层中碳化钨颗粒的溶解程度密切相关,钒优先将碳化钨颗粒分解出的碳原子以碳化钒形式固定,从而抑制了碳化钨颗粒的分解,钒元素含量决定了碳化钨溶解的强弱,含有2%钒元素的堆焊层中生成适量碳化钒有效抑制了碳化钨的溶解.钒元素的加入还能强化碳化钨堆焊层基体金属的硬度,降低堆焊层中碳化钨颗粒剥落的风险,有效提高了堆焊层的耐磨性.     

Low stress abrasive wear behavior of a hardfaced steel

A plain carbon steel was overlayed with a wear-resistant hardfacing alloy by manual arc welding. Low stress abrasive wear tests were conducted with an ASTM rubber wheel abrasion tester using crushed silica and as the abrasive medium. The wear rate decreased with sliding distance, and there was an overall improvement in the abrasive wear resistance as a result of overlaying. The wear behavior of the samples has been discussed in terms of microstructural features while the examination of wear surface and subsurface regions provides insight into the wear mechanisms.