起重吊具用合金鋼材之熱鍛模擬、熱處理與機械性質之研究

The Study on Forging Simulation, Heat Treatment and Mechanical Properties of Alloy Steels for Industrial Lifting Accessories

徐宇彤(Yu-Tung Hsu)

指導教授 ： 林新智

國立臺灣大學/工學院/材料科學與工程學研究所/博士(2019年)

https://doi.org/10.6342/NTU201903942

摘要

歐美等重工業開發較早之國家，已於百年前開創了起重吊具產業。起重吊具產業為一獨特產業類別，其應用領域非常廣泛，包括陸上和海上能源、建築和基礎設施、貨物裝卸、船舶牽引以及採礦運輸等等。由於應用廣泛，隨著長時間的經驗累積及開發改善，產業界也開始制定各式各樣的製造及使用規範。現今市場之起重吊具產品多為鍊條、鋼索搭配扣環、掛鉤的系統組合。本研究與台灣起重吊具產業龍頭¬¬ – 振鋒公司產學合作，進行起重吊具系統中部件的精進與研究開發。
首先針對80級起重吊具產品進行改善提升。目前80級起重吊具的應用已經相當成熟，商品供應量也相對穩定。80級起重吊具部件多採取鍛造成型，再經由熱處理調質已達到應用之需求。本研究針對振鋒公司銷量最好之80級吊鉤單品進行改善。透過電腦輔助工程進行熱鍛造起始溫度變化對鍛造製程影響之模擬，發現現行量產所採用的1200oC鍛造起始溫度過高。研究結果顯示過高之鍛造溫度會造成材料表面脫碳及產生鍛造過熱組織，過低之鍛造溫度則會造成鍛胚破裂，因此理想熱鍛造起始溫度應為1000oC-1100oC之間。
接著針對100級起重吊具用產品進行研發探討。100級起重吊具大量使用合金鋼材進行調質熱處理以達到設計強度需求。本研究針對商用鋼種SAE 4140及振鋒公司與中鋼公司開發之Yoke 8625M合金鋼材進行熱處理開發與機械性質測試，以了解淬火回火處理對100級鋼種機械性能的影響。研究成果顯示兩種材料經過適當熱處理皆可符合100級應用之產業規範需求，尤其Yoke 8625M之低溫衝擊韌性優異更提升了此材料在離岸及低溫環境使用之潛力。
針對120級起重吊具產品，本實驗室與振鋒公司及中鋼公司之共同研究，透過合金設計開發新一代120級用高強度、高韌性、高硬化能合金鋼Yoke 8625MS。研究結果顯示Yoke 8625MS透過Ni、Mo、B等元素的添加大幅提升了材料的硬化能，同時也提升了材料的機械強度及低溫韌性。此材料的成功開發也使的未來在120級起重吊具產業更具競爭力。

關鍵字

起重吊具用鋼 ； 熱鍛造模擬 ； 熱處理 ； 機械性質 ； 硬化能

並列摘要

Europe and United State is the leader in the heavy lifting, rigging, and securement industries. The heavy lifting industry is a unique industry category with a wide range of applications, including onshore and offshore energy facility, construction engineering, infrastructure, cargo handling, ship towing, mining and transportation…etc. Due to the wide range of applications, with the accumulation of experience and development over a long period of time, the industry has also begun to draw up a wide range of manufacturing and usage specifications. In current market, the heavy lifting products are mostly systemized with combinations of chains, wire ropes with riggings and hooks. This research was carry out by cooperating with the heavy lifting industry leader of Taiwan - YOKE Company.
First of all, we focus on improving and upgrading the grade 80 lifting products. At present, the application of grade 80 lifting accessories is quite mature, and the supply and demand is relatively stable. The grade 80 lifting accessories are mostly forged and heat treated to meet the application requirements. This study is aiming at improving the forging process of the best-selling grade 80 hook produced by YOKE. Through computer assisted engineering (CAE), we found that the 1200oC forging starting temperature used in the current mass production was too high. The results show that the excessive forging temperature will cause decarbonization at the surface of the material and also induced typical overheated structure – Widmanstatten structure. Deficient forging temperature may cause the forging embryo to rupture. Therefore, the ideal hot forging starting temperature should be between 1000oC and 1100oC.
Then we focus on the research and development of grade 100 lifting products. Grade 100 lifting components are mostly manufactured by quenched and tempered alloy steels. This study is aiming at understanding the effect of quench and temper treatment on the mechanical properties of commercial steel SAE 4140 and Yoke 8625M alloy steel developed by YOKE and China Steel Company. The results show that both materials can meet the industrial specification requirements of grade 100 applications after proper heat treatment. In particular, the excellent low temperature impact toughness of 8625M enhances the potential of this material in offshore and low temperature environments.
Furthermore, we focus on the development of new generation high strength, high toughness, high hardenability alloy steel – Yoke 8625MS. The research results show that Yoke 8625MS greatly enhances the hardenability, improves the mechanical strength and low temperature toughness of the material through the addition of Ni, Mo, B and other elements. The successful development of Yoke 8625MS material also makes YOKE more competitive in the grade120 heavy lifting industry.

並列關鍵字

industrial lifting used steel ； hot forging simulation ； heat treatment ； mechanical properties ； hardenability

參考文獻

參考文獻

[1] ASTM A413 / A413M-07(2012), Standard Specification for Carbon Steel Chain, ASTM International, West Conshohocken, PA, 2012, www.astm.org

[2] ASTM A391 / A391M-07(2012), Standard Specification for Grade 80 Alloy Steel Chain, ASTM International, West Conshohocken, PA, 2012, www.astm.org

[3] ASTM A973 / A973M-07(2012), Standard Specification for Grade 100 Alloy Steel Chain, ASTM International, West Conshohocken, PA, 2012, www.astm.org

[4] ASTM A906 / A906M-02, Standard Specification for Grade 80 and Grade 100 Alloy Steel Chain Slings for Overhead Lifting, ASTM International, West Conshohocken, PA, 2002, www.astm.org