Mr. Choi,

I think you have a wrong concept about Temperature Limitation and Material, and Allowable Stress.
ASME Sec.II Part D shows a lot of data in mechanical, metallurical and physical properties which are based on the elastic design. As you know, most of the conventional austenitic steels (e.g., 316H, 316, 309, 310, 304H, etc.) for high temperature have the same max. limit as 1500 deg.F (for ASME sec.VIII Div.1) in ASME Sec.II Part D.

As far as I know your facility must be Fired Heater or Furnace. You have to design the facility with plastic concept including creep-rupture for your facility according to API STD560, STD530, RP579, and RP573. You can find some different data for allowable stress/temperature limit of each material.

As a result, your present materials should be replaced with the following materials;

HK-40 (310SS)
HP series
Alloy 800H

Also you have to consider the following factors for each candidate material;

(1) tube wall thickness per creep-rupture design
(2) high temperature corrosion in your service: oxidation, sulfidation, carburization, V attack, nitriding, molten products, etc.
(3) fatigue stress due to cyclic service
(4) erorion due to high velocity, particles, and geometry effects (e.g., high curvature)
(5) life time and cost evaluation

Hope it helps,

Thomas J.C. Eun



글쓴이:최주영 번호: 7387 번글 조회: 150 추천: 2


당사에서는 Max. 운전온도 850℃,2 kg/cm2G(Steam)운전조건에서
재질은 304H Stainless Steel Tube를 사용하고 있습니다.
내부 Inspection 결과 고온접촉 부위에서 고온부식이 진행되고 있습니다.
304H Stainless Steel을 310S 또는 Inconel로 변경하려고 합니다.
310S Stainless Stell의 사용온도는 304H 보다 높은 것으로 알고 있으나
ASME에서는 304H와 동일한 온도로 규정되어 있어 사용이 가능할 지 궁금
합니다.Inconel로 변경할 경우 금액이 너무 과다할 것 같아 적당한 재질을
검토 중입니다. 답변부탁드립니다.