耐衝磨硬面焊合金之研究

Anti-Impact-Wear Hardfacing Alloys

謝鎮宇(Hsieh, Chen Yu)

指導教授 ： 林樹均

國立清華大學/工學院/材料科學工程學系/碩士(2015年)

摘要

一般商用之硬面焊合金以高鉻鑄鐵為主，且大多數相關研究也以其為基礎去做改良。而本實驗室以高熵合金的觀念為基礎，採用多元合金元素添加，配合添加硼、碳元素，形成多元的碳化物、硼化物強化相，期望得到更耐磨的硬面焊合金；其中耐磨評估以棒對氧化鋁砂輪帶的擦損磨耗為主，目前最佳的成分是THA合金(Al1.3Cr18.4Fe38.7Mn4.4Ni2.2Mo0.4Nb4.4B28.0C2.2)，其磨耗阻抗為傳統高鉻鑄鐵的12倍。為了使磨耗測試結果更真實反映產業應用，自行設計衝磨試驗機，利用空壓機提供動力，使黏有試片的衝頭垂直輾壓石英顆粒；結果顯示此種衝磨試驗能真實反映出產業應用的耐磨能力。
本研究以三個不同系統為出發點，分別為HFe-HC系列、UP系列和THA系列，探討其耐衝磨能力。在HFe-HC系列中，HFe-HC 3因具有極佳的韌性，而得到最好的耐衝磨性，但本身硬度過低，重量損失仍偏高；UP系列則是先實際利用真空電弧熔煉來製備，衝磨試驗後，以266合金為最佳；在以不同手法來進行優化，包括析出強化、基地相改質、改變硼、鐵含量等，並對整個系列做統整，發現良好的耐衝磨性須具備一定的硬度和韌性，且析出相和基地相的比率也有關聯；THA合金系列是藉由鎢的固溶來使合金的硬度及韌性提高，THA-0.25W為本研究最佳耐衝磨性之合金，其重量損失為2.2 mg/h。

關鍵字

硬面焊 ； 衝磨 ； 合金 ； 磨耗

並列摘要

High chromium cast irons (HCCIs) are the typical commercial hardfacing alloys and many studies try to improve their properties. Based on the concepts of high entropy alloys, multi-element hardfacing alloys were developed. Pin-on-belt testing was used to evaluate the abrasion-resistant ability of these alloys. The most abrasion-resistant alloy was the THA alloy (Al1.3Cr18.4Fe38.7Mn4.4Ni2.2Mo0.4Nb4.4B28.0C2.2) and its abrasion-resistance was about 12 times of the traditional HCCIs. However, this abrasion testing results cannot imply to real cement industries. In order to reflect industrial application more truly, a new impact-wear test machine was designed. The sample which is stick to one punch moves vertically to crush quartz particles. The results show this impact-wear test can truly reflect wear-resistant properties in industrial application.
Three alloy systems of HFe-HC series, UP series and THA series were used to study their impact-wear abilities. In HFe-HC series, the HFe-HC 3 alloy has the best anti-impact wear properties because of its highest toughness. However, the hardness of HFe-HC 3 is so low that its weight loss rate is still high. In UP series prepared by vacuum arc melting, the 266 alloy (Fe51.1Cr25.1Mn0.6Ni0.1Si1.3B0.4C21.4) was the best anti-impact- wear alloy. The composition of the 266 alloy was modified to improving its anti-impact-wear property via changing Fe and B content, adding precipitation hardening elements, or modifying matrix elements. We found two modified 266 alloys have the same anti-impact-wear properties (weight loss rate is 2.6 mg/h) as that of the 266 alloy. The hardness, toughness, and microstructure of alloys can intricately affect their impact-wear properties. In THA series, hardness and toughness can be improved by adding 0.25 at% tungsten into the THA alloy. The THA-0.25W alloy has the best anti-impact-wear properties and its weight loss rate is 2.2 mg/h.

並列關鍵字

hardfacing ； impact-wear ； alloy ； wear

參考文獻

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