อิทธิพลของโครงสร้างต่อความต้านทานการสึกหรอของเหล็กกล้า

Effect of Microstructure on Wear Resistance of High Manganese Steel

Name: นาตยา ต่อแสงธรรม

Name: Nattaya Tosangthum

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: High Manganese Steel

; Cast Structure

; Wear Testing

; Wear Resistance

; Effect of Microstructure on Wear

Abstract: This research project investigates the influence of microstructure on wear resistance of highmanganese steel containing 1.15% C, 13% Mn and 0.5% Si. Wear testing was carried out bysimulating the process using a jaw crusher, conforming to ASTM G81-97 standard. Test specimenmicrostructures were achieved by varying the amount of scraps in charge materials, pouringtemperature and by heat treatments. The charges were melted in an induction furnace. Then the melt was poured in CO2 sand molds at 1470 ?C and 1430 ?C pouring temperatures employing 0%, 40% and 80% high manganese scraps. The heat treatments used involved heating the sample at 1,050?C and 1,150 ?C followed by water, oil, and air quench. Microstructure examination and hardness testings were carried out in the as-cast, heat-treated and after wear test conditions.The macrostructure of the castings consist of chill, columnar and equiaxed zones. The grain size inchill zone are almost the same in all castings. When the amount of the scraps in charge materialswas increased from 0% to 80% the average lengths of columnar grains were found to increase 4.73mm. The average equiaxed grain size was also found to decrease 1.5 mm. and the amount ofimpurity increase from 0.65% to 1.15% by unit area. The amount of carbide in as-cast conditionwere almost the same irrespective of %scrap. The equiaxed grain sizes of the castings are dependent on pouring temperatures. At pouring temperatures of 1430 ?C and 1470 ?C, average grain sizes were found to be 0.2 mm. and 1.22 mm. respectively. At higher heat treatment temperature of 1,150 ?C, the larger grain size and larger carbide were obtained than 1050 ?C. Besides that, the amount of carbide after quenching was increased from 0.02% to 3.6% by unit area when the cooling rate decreased by using water and air quench respectively. The hardness of as-quench specimen was found to be slightly dependent on %scrap. It increased about 11.25% when %scraps decreased from 80% to 0%.The hardness was also found to be slightly dependent on the amount of carbide.It increased about 4.85% when the amount of carbide decreased from 3.6% to 0.02% by unit area. The result of wear resistance testing under the same condition showed that the wear ratio was found to decrease from 2.404 to 0.806 as average equiaxed grain size decreased from 2.72 mm. to 1.22 mm. The wear ratio was also found to increase from 0.893 to 1.183 as the amount grain boundary carbide after heat treatment increased from 0.04% to 3.6% by unit area. Finally the wear ratio was found to decrease from 2.404 to 0.806 as the amount of impurity increased from 0.22% to 1.15% by unit area. It can concluded that the microstructure of high manganese steel i.e. grain size, amount of carbide and amount of inclusions have influence on gouging wear resistance. Smaller austenitic grain size, small amount of carbide and inclusions content were the best resisting wear.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร

Email: info.lib@mail.kmutt.ac.th

Name: ปัญญา ศรีจันทร์

Role: อาจารย์ที่ปรึกษา

Created: 2545

Issued: 2005-11-11

Modified: 2559-01-14

วิทยานิพนธ์/Thesis

ISBN: 9744560029

CallNumber: MT191

tha

DegreeName: วิศวกรรมศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีวัสดุ

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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3	MT191ab.txt	3.22 KB	35	2018-05-13 05:46:36

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