Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


공학

한국표면공학회지 (34권6호 575-584)

Evaluation on erosion resistance of STS304 by flyash

Flyash에 의한 STS304 재료의 내침식성 평가

박해웅;이의열;

한국기술교육대학교 신소재공학과;안동대학교 신소재공학부;

Abstract

Erosion due to abrasive particles contained in gas streams from boilers has been emerged as a significant problem in the coal fired power plants. Particle erosion accounted for approximately 50% of boiler failures and especially flyash erosion was responsible for 20~30% of emergency boiler shutdowns. Particularly, because of the high ash loading and high velocity, most erosion occurs in the boiler tubes and economiser tube bank where the direction of the gas stream changes to $180^{circ}$ .In this study, a high temperature particle erosion tester was used to evaluate erosion rate in a simulated environment. The erosion parameters such as erosion temperature, particle impact angle, particle velocity and various particle size were changed. Flyash is the combustion product of the pulverized coal, where size is ranging from 1 to $200mu extrm{m}$. Flyash composed of mainly SiO$_2$, $A1_2$$_O3$, and $Fe_2$$O_3$has dense spherical particles and irregular particles containing numerous pores and cavities. From the erosion tests at various conditions, the maximum erosion was experienced at impact angles of $30^{circ}$ to $60^{circ}$ In addition, erosion rate increased in proportional to velocity and temperature. And from the observation of the eroded surfaces, it was also concluded that 304 stainless steel was mainly eroded by extrusion-forging at high impact angle ($90^{circ}$) and by microcutting mechanism at low impact angles ($30^{circ}$ and $45^{circ}$).

Keywords