| Research Abstract |
The abrasive phenomenon that a material surface is damaged or removed by the collision of particles is called the "erosion". In the erosive wear, many factors are concerned, and appearing characteristic complicatedly changes. Therefore, it is present state that there is no an engineering technique which accurately estimates largest lesion and wear life without also sticking to mainly utilizing for the transportation of the particles, and wear and damage cases by the erosion such as pipe line occurring in great numbers.
In this study, steel material used as an object material well industrially most was taken up. Wear experiment by the blast test machine was carried out in order to propose fundamental technique in erosive wear experiment of steel material and evaluation method of wear amount. Mild steel material (SS400) was used first of all as an object material. The particle used the steel ball grit.As evaluation criterion of wear amount, "erosion rate" defined at volume damage quantity
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per unit particle mass was proposed. As a result of the experiment by this technique, the damage rate of the mild steel material became a maximum at 20゜〜30゜ impact angle, and that it became once a minimum in the 60゜ vicinity and shows the characteristic angle dependence of taking maximal value at 80゜〜90゜ again clarified.
And, the similar erosion experiment was carried out on mild steel and carbon steel. The
mild steel is steel material next widely used for carbon steel, and the stainless steel is steel material used as bend pipe and pipe joint, chemical industry. According to the result, the carbon steel showed the damage rate curve of twin-peak type with two peaks in low angle side 20゜〜30゜ and high angle side 80゜〜90゜. Though the angle dependence of ferrite system and martensitic stainless steel is twin-peak type as well as the SS material, the largest wear amount is 80゜ 〜90° in the high angle side. In austenitic, it is 20°, and the largest wear amount is shown, and in the high angle side, it monotonously decreases. Like the above, the steel material clarified that wear amount and impact angle dependence remarkably differed by the structure and hardness. In addition, the erosive wear under the high temperature environment was investigated. As the result, mechanical property of target material and shape of particles clarified being greatly concerned in the erosion rate, and the wear characteristic (the impact angle dependence) were grasped. And, the high-hard high chromium cast iron was also tested. As the result, the erosion wear advanced from the ordinary temperature, and it was clarified to be effective in the high temperature as a erosion-proof material. Less
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