权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Creation of Easy-to-Recycle Sintered Steels. Replacement of Copper Addition to Boron.

制造易于回收的烧结钢。

基本信息

批准号：
11450276
负责人：
KUROKI Hidenori
金额：
$ 5.25万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450276/
关键词：
recycle sintered material boron Fe-B-C eutectic mechanical property

项目摘要

A boron of 0.03-0.125mass% and a carbon of 0-1mass% are simultaneously added in iron powder to promote sintering by forming a eutectic melt of Fe-B-C during heating. Sintering conditions are varied in temperature of 1380-1440 K and in holding time of 0-180 min. The dimensional change during sintering is observed by a dilatometer. The presence of eutectic melt during sintering has been verified by the observation with optical microscope and SEM.The tensile strength and elongation of sintered materials are measured. Some specimens are subjected to post-sintering heat treatment of quenching and annealing to improve mechanical properties.The results are as follows.(1) The simultaneous addition of boron and carbon in iron powder forms eutectic melt at and above 1410 K.The differential dilatometric curve of Fe-0.05mass%B-1.0mass%C material coincides well to that of conventional copper added sintered steel. The coincidence would be the result of the occurrence of nearly the same amount of eutectic melt as well as the expansion of ferrite with the solid solution of carbon.(2) The eutectic forms three dimensional network between iron particles. With slow cooling rate, the boundary with eutectic behaves as the precipitating site of Fe_3C during γ-α phase transformation. Therefore, the outer part of iron particles becomes ferrite and only the center part of the particles forms pearlite.(3) The tensile strength of both boron and carbon doped materials mainly depends on the amount of pearlite or ferrite, which vary with the effective amount of carbon, than the amount of the eutectic. The excessive addition of boron reduces effective amount of carbon. With a boron of 0.1mass% or more, the strength decreases.(4) Fe-0.05mass%B-1.0mass%C material can sinter at 1440 K with a microstructure consists of the eutectic and pearlite with a small amount of ferrite, which results good mechanical properties. The strength of this material can be improved by quenching and annealing.

在铁粉中同时加入0.03-0.125质量%的硼和0-1质量%的碳，加热时形成Fe-B-C共晶熔体，从而促进烧结。烧结条件不同，温度为1380-1440K，保温时间为0-180min。用膨胀仪观察了烧结过程中的尺寸变化。通过光学显微镜和扫描电子显微镜的观察，证实了烧结过程中共晶熔体的存在，并测量了烧结材料的抗拉强度和伸长率。对一些试件进行了淬火和退火的烧结后热处理，以改善力学性能。结果表明：(1)在1410K及以上的温度下，在铁粉中同时添加硼和碳形成共晶熔体。Fe-0.05质量%B-1.0质量%C材料的差热膨胀曲线与常规添加铜的烧结钢的差热膨胀曲线吻合较好。这种重合可能是由于共晶熔体的数量几乎相同，以及铁素体与碳的固溶体的膨胀所致。(2)共晶在铁颗粒之间形成了三维网络。冷却速度较慢时，共晶界在γ-α相变过程中表现为Fe3C的析出部位。因此，铁颗粒的外部形成铁素体，只有颗粒的中心部分形成珠光体。(3)硼和碳掺杂材料的抗拉强度主要取决于珠光体或铁素体的数量，而不是共晶量，珠光体或铁素体的数量随有效碳量的变化而变化。过量添加的硼减少了有效碳量。(4)Fe-0.05质量%B-1.0质量%C材料可在1440K烧结，显微组织为共晶+珠光体+少量铁素体，具有良好的力学性能。这种材料的强度可以通过淬火和退火来提高。