《grade-310s不锈钢高温性能》由会员分享，可在线阅读，更多相关《grade-310s不锈钢高温性能（5页珍藏版）》请在金锄头文库上搜索。
1、North American Stainless Long Products Stainless Steel Grade Sheet AISI 310S UNS S31008 EN 1.4845 AISI 314 UNS S31400 EN 1.4841 INTRODUCTION Types 310S SS and 314 SS are highly alloyed austenitic stainless steels designed for service at elevated temperature. The high Cr and Ni contents enable this a
2、lloy to resist oxidation in continuous service at temperatures up to 2200F provided reducing sulfur gases are not present. In intermittent service, 310S SS can be used at temperatures up to 1900F as it resists scaling and has a relatively low coefficient of expansion. Increased level of silicon in 3
3、14 SS further improves oxidation resistance at higher temperature. Carburizing atmosphere may reduce the total life depending on the actual conditions. However, these grades have superior resistance compared to lower-chromium-nickel grades. These grades are used for their high-temperature oxidation
4、resistance for applications such as furnace parts, furnace conveyer belts, insulation holding studs, etc. PROUDCTS AVAILABLE Wire Rod. See product sheet for dimensions, tolerances, finishes available and other details. Standard Chemical Composition Elements C MN P S SI CR NI UNS 31000 AISI 310 Min 2
5、4.00 19.00 Max 0.25 2.00 0.045 0.030 1.50 26.00 22.00 UNS 31008 AISI 310S Min 24.00 19.00 Max 0.08 2.00 0.045 0.030 1.50 26.00 22.00 UNS 31400 AISI 314 Min 1.50 23.00 19.00 Max 0.25 2.00 0.045 0.030 3.00 26.00 22.00 Nominal Mechanical Properties (annealed condition) Tensile Strength ksiMPa Yield Str
6、ength ksiMPa % Elongation 4d % Reduction in Area 95655 45310 50 60 NOMINAL PROPERTIES AT ELEVATED TEMPERATURES The properties quoted below are typical of annealed 310S and 314 SS. These values are given as a guideline only, and should not be used for design purposes. NOMINAL PHYSICAL PROPERTIES PROC
7、ESSING & FABRICATION ANNEALING Annealing is achieved by heating to between 1900F and 2050F for 60 minutes per inch thickness followed by water quenching. Annealing will ensure that any carbide precipitates are dissolved back in solution. COLD WORKING These grades can be drawn into wire, formed into
8、parts (bending) and cold headed without any difficulty. Severe cold-forming operations should be followed by annealing. WELDING These grades can be satisfactorily welded and brazed by most conventional methods, giving a tough weld. Welding procedures should be selected with care in order to avoid ho
9、t cracking due to the fully austenitic weld microstructure obtained from using matching filler metals. OXIDATION AND CORROSION RESISTANCE OXIDATION In many processes, isothermal (constant temperature) conditions are not maintained and process temperatures vary. Expansion differences between the base
10、 metal and the scale during heating and cooling can cause cracking and flaking of the protective scale. This allows the oxidizing media to attack the exposed metal surface. The repeated flaking will reduce the cross section and parts will fail. The spalling resistance is greatly improved with the hi
11、gher nickel contents in these grades because nickel reduces the expansion differential between the scale and the base metal. EFFECT OF ATMOSPHERE An increase in corrosion rate can be expected in the presence of water vapor for the traditional 18/8 type stainless steels. The increased nickel and chro
12、mium contents of 310 and 314 provide good resistance to moist air at elevated temperatures. FLUE GASES It is extremely difficult to generalize corrosion rates in flue and process gases since gas composition and temperature may vary considerably within the same process unit. Combustion gases normally
13、 contain sulfur compounds, as sulfur dioxide is present as an oxidizing gas, along with carbon dioxide, nitrogen, carbon monoxide and excess oxygen. Protective oxides are generally formed and, depending on exact conditions, the corrosion rate may be similar or slightly greater than for service in ai
14、r. Reducing flue gases contain varying amounts of hydrogen sulfide, hydrogen, carbon monoxide, carbon dioxide and nitrogen. The corrosion rates encountered in these environments are sensitive to hydrogen sulfide content and temperature, and satisfactory material selection often necessitates service
15、testing. CARBURISATION High chromium and nickel contents result in a slower diffusion rate of carbon into the steel. 310 and/or 314 therefore have good resistance to carburizing atmospheres. DISCLAIMER The material contained in this Web Page/Sheet has been designed as a guide for customers of North
16、American Stainless. However, the material contained herein is not intended as a substitute for any persons procedures and should not be used or relied upon for any specific or general application without first obtaining competent advice. Furthermore, North American Stainless disclaims any responsibility for the suitability of the steel in question for any particular purpose or for the performance or selection of the steel, unless North American Stainless specifically auth
