{"title":"Environmental impact evaluation of wear protection materials","authors":"H. Rojacz , D. Maierhofer , G. Piringer","doi":"10.1016/j.wear.2024.205612","DOIUrl":null,"url":null,"abstract":"<div><div>Wear protection materials, especially those for high-temperature service, often contain substantial amounts of chromium, cobalt and/or nickel and/or with embedded hard phases or forming harder intermetallic phases. Due to the comparatively high environmental impact of those elements, more sustainable alternatives must be found. This study presents a life cycle assessment quantifying the environmental impacts of three groups of cast alloys for wear protection: iron-, nickel-, and cobalt-based alloys. The assessment includes the production stage from raw materials extraction to casting (upstream impacts from cradle-to-gate), with the functional unit defined as 1 dm³ wear protection material. Global average process data were used to estimate the environmental impact of the respective alloy. Results indicate that iron-based alloys as studied here cause lower greenhouse gas (GHG) emissions during production (57–103 kg CO<sub>2eq</sub>/dm³ or 8.4–13.8 t CO<sub>2eq</sub>/t) compared to nickel-based (185–205 CO<sub>2eq</sub>/dm³ or 20–22 t CO<sub>2eq</sub>/t) and cobalt-based alloys (318–347 CO<sub>2eq</sub>/dm³ or 31.2–39.5 t CO<sub>2eq</sub>/t). The lowest emissions during production are caused by iron aluminide-based alloys at around 57 kg CO<sub>2eq</sub>/dm³ or approx. 8.4 t CO<sub>2eq</sub>/t, which is up to 90 % less than cobalt-based alloys, of up to 60 % less than nickel-based alloys, and around 50 % relative to Cr-rich iron-based alloys. Further, lifetime considerations based on actual wear data of the respective alloys at ambient and elevated temperatures were accounted for, and three different case studies were evaluated, namely abrasive wear at feeder plates, erosive wear on sieves (both at ambient and high temperatures) as well as wear on grate bars of a sintering plant for pig iron. Here, it was shown that the wear materials’ lifetime of wearing materials has a crucial effect on the environmental impact, since a prolonged lifetime reduces the need for spare parts and of replacement of the goods with their embedded carbon footprint. For example, an average hot sieve can achieve GHG emission savings of approx. 50 t CO<sub>2eq</sub>/a when using an iron-aluminium alloy instead of a cobalt-based wear protection. The exchange of 10 m³ worn grate bars for a sintering plant made of an iron aluminide instead of a white cast iron saves over 500 t CO<sub>2eq</sub>/a. Further, over 50 % emission savings in other environmental impact categories can be achieved by this measure.</div></div>","PeriodicalId":23970,"journal":{"name":"Wear","volume":"560 ","pages":"Article 205612"},"PeriodicalIF":5.3000,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Wear","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0043164824003776","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Wear protection materials, especially those for high-temperature service, often contain substantial amounts of chromium, cobalt and/or nickel and/or with embedded hard phases or forming harder intermetallic phases. Due to the comparatively high environmental impact of those elements, more sustainable alternatives must be found. This study presents a life cycle assessment quantifying the environmental impacts of three groups of cast alloys for wear protection: iron-, nickel-, and cobalt-based alloys. The assessment includes the production stage from raw materials extraction to casting (upstream impacts from cradle-to-gate), with the functional unit defined as 1 dm³ wear protection material. Global average process data were used to estimate the environmental impact of the respective alloy. Results indicate that iron-based alloys as studied here cause lower greenhouse gas (GHG) emissions during production (57–103 kg CO2eq/dm³ or 8.4–13.8 t CO2eq/t) compared to nickel-based (185–205 CO2eq/dm³ or 20–22 t CO2eq/t) and cobalt-based alloys (318–347 CO2eq/dm³ or 31.2–39.5 t CO2eq/t). The lowest emissions during production are caused by iron aluminide-based alloys at around 57 kg CO2eq/dm³ or approx. 8.4 t CO2eq/t, which is up to 90 % less than cobalt-based alloys, of up to 60 % less than nickel-based alloys, and around 50 % relative to Cr-rich iron-based alloys. Further, lifetime considerations based on actual wear data of the respective alloys at ambient and elevated temperatures were accounted for, and three different case studies were evaluated, namely abrasive wear at feeder plates, erosive wear on sieves (both at ambient and high temperatures) as well as wear on grate bars of a sintering plant for pig iron. Here, it was shown that the wear materials’ lifetime of wearing materials has a crucial effect on the environmental impact, since a prolonged lifetime reduces the need for spare parts and of replacement of the goods with their embedded carbon footprint. For example, an average hot sieve can achieve GHG emission savings of approx. 50 t CO2eq/a when using an iron-aluminium alloy instead of a cobalt-based wear protection. The exchange of 10 m³ worn grate bars for a sintering plant made of an iron aluminide instead of a white cast iron saves over 500 t CO2eq/a. Further, over 50 % emission savings in other environmental impact categories can be achieved by this measure.
期刊介绍:
Wear journal is dedicated to the advancement of basic and applied knowledge concerning the nature of wear of materials. Broadly, topics of interest range from development of fundamental understanding of the mechanisms of wear to innovative solutions to practical engineering problems. Authors of experimental studies are expected to comment on the repeatability of the data, and whenever possible, conduct multiple measurements under similar testing conditions. Further, Wear embraces the highest standards of professional ethics, and the detection of matching content, either in written or graphical form, from other publications by the current authors or by others, may result in rejection.