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【stainless steel grade Terminology】 ----------------
1 [ hierarchical classification ] ( 1 ) National Standard GB ( 2 ) industry standard YB ( 3 ) local standards ( 4 ) enterprise standard Q / CB ---------------- (2) [ Category ] ( 1 ) Product Standard ( 2 ) Packaging Standard ( 3 ) Standard Methods ( 4 ) basic standards ---------------- 3 [ standard level ] Y class : the international advanced level Class I : International general level Class H : domestic advanced level ---------------- 4 [ GB ] GB1220-84 stainless steel rods (I grade ) GB4241-84 stainless steel weld plate Park (H level ) GB4356-84 stainless steel weld plate park (I grade ) GB1270-80 stainless steel pipe (I grade ) GB12771-91 stainless steel pipe (Y class ) GB3280-84 stainless steel cold plate (I grade ) GB4237-84 stainless steel hot plate (I grade ) GB4239-91 stainless steel cold strip (I grade ) ======================== 【stainless steel quality Terminology 】 ---------------- 1 [ Material ] (1) DDQ material (deep drawing quality) Is used for deep drawing ( punch ) use of the material , that is, we said soft material, this material is characterized by a high elongation (≧ 53%), low hardness (≦ 170%), internal grain grading between 7.0 to 8.0 , excellent deep drawability . Many manufacturing vacuum flask, pot class enterprise, its products processing ratio (BLANKING SIZE / Products diameter ) generally higher, respectively, than their processing 3.0,1.96,2.13,1.98 . SUS304DDQ timber is mainly used for processing these requests higher than that of the product, of course processing ratio of more than 2.0 products are generally subject to a few times a stretch to complete. If the material aspects of extending the reach of words , in the processing of deep drawing products when products easy to crack , pulling wear phenomenon, affecting the rate of qualified products , of course, will increase the cost of manufacturers ( 2 ) General Material Mainly used in addition to material outside DDQ purposes , this material is characterized by relatively low elongation (≧ 45%), while the hardness is relatively high (≦ 180), internal grain grade of 8.0 to 9.0 , and DDQ timber comparison , it is relatively deep drawability somewhat less , it is mainly used without thrust will be able to get products , like a kind of tableware spoon , spoons and forks , electrical appliances , steel uses. But it is an advantage compared DDQ material is relatively good BQ , mainly because of its higher hardness sake . ---------------- (2) [ Surface Quality ] Stainless steel sheet is an inexpensive material , but the surface quality requirements of its customers is very high . Stainless steel sheet in the production process inevitably there will be a variety of defects , such as scratches, pits , sand hole , dark lines , creases , pollution , etc., so that its surface quality, such as scratches , creases , etc. These defects are advanced materials allowed , while pitting, sand holes this defect in the spoon, spoon , fork, making time is not allowed because when polishing hard to discard it . We face a variety of defects according to the extent and frequency of appearance , to determine the quality level of its tables , thus to determine the product level . ( See Table :) | Uses | Objects products | processing | quality characteristics required | Production Process | Surface Quality | BQ sex | Material | Shape | thickness tolerances | welding | corrosion | Shallow Processing knives, forks and other extended horizontal blanking → ??→ → forming → ??cutting head polishing → ??cleaning → ??packaging must not have defects such as pitting general general material generally does not require good -5% Deep processing of class II dinnerware , mug , etc. oiled blanking → ??→ forming → ??( sometimes several times ) Trimming curling → ??washing → → → → polishing compound bottom welding handle creases → Packaging may not have scratches and other defects generally DDQ requirements high -3 -5% good PIPE decorative tubes extruded molding narrowband → → → polished butt weld pipe cutting → ??→ → → polishing grinding mouth creased packaging may not have material defects such as General General Good Good Fair -8% The outer wall of the freezer and other kitchen utensils blanking → ??folding → ??Welding → ??sanding may not have creases material defects such as General General General General -8 % good Drinking water heater tank container narrowband → Roll → Welding → ??cutting → ??→ polished bottom seam welding → ??Packaging Fair Fair Fair Good Fair timber generally -10 % ---------------- 3 [ thickness tolerance ] Stainless steel products in general different from its raw material requirements also vary thickness tolerances , like second-class tableware and mug , thickness tolerances generally higher, -3 to 5%, while a thickness tolerance tableware General requirements - 5% -10 % steel such requests , hotels with a freezer timber thickness tolerance requirements -8 % , operator requirements for thickness tolerances generally between -4% to 6% . While export products of different raw materials will lead to customer requirements of different thickness tolerances . General export products customer thickness tolerances are higher, while domestic enterprises is relatively low thickness tolerances ( mostly because of cost considerations ) , some customers even ask -15%. ---------------- 4 [ welding ] Usage of different performance requirements for welding are also different . A class of cutlery on the welding performance in general is not required , even including some pan class enterprises. But the vast majority of products require materials welding performance is good , like second-class tableware , mug , steel pipes, water heaters, water dispenser . ---------------- 5 [ corrosion ] Most stainless steel products require good corrosion resistance , like a second class tableware, kitchenware , water heaters , drinking fountains , and some foreign suppliers of the product also made corrosion resistance test: NACL solution heated to boiling , pour over time out solution , wash drying, weigh loss , to determine the extent of corrosion ( Note: The product polishing , because of emery cloth or sandpaper ingredients containing Fe , will lead to testing the surface rust ) ---------------- 6 [ polished performance ] Today's society in the production of stainless steel products generally are polished in this process , only a few products such as water heaters, drinking fountains , etc. do not need polishing liner . Therefore, this requires a good polishing performance materials . The main factors affecting polishing performance are the following: ( 1 ) Raw material surface defects. Such as scratches , pitting , over- pickling . ( 2 ) raw material problem . Hardness is too low, it is not easy to throw light polishing (BQ is bad ) , and the hardness is too low, the surface tension in the deep prone to orange peel , thus affecting BQ property . BQ relatively high hardness like. ( 3 ) After a deep-drawn products, areas of extreme deformation of the surface will be a small black dots and RIDGING, thus affecting BQ property . ---------------- 7 [ heat resistance ] Is the high temperature heat resistance . Carbon : Carbon in austenitic stainless steel is strong and stable austenite formation and expansion of austenite elements. The ability of carbon to austenite is about 30 times that of nickel , carbon is an interstitial element , by solid solution strengthening can significantly improve the strength of austenitic stainless steel . Carbon can also improve the austenitic stainless steel in a high concentration of chloride ( eg boiling 42% MgCl2 solution ) in the resistance to stress corrosion. However , in austenitic stainless steel , carbon is often seen as harmful elements , mainly due to the stainless steel and corrosion of some of the conditions ( such as welding or by heating 450 ~ 850 ℃ ) , with the carbon in the steel chromium to form chromium Cr23C6 Carbon compounds resulting in partial depletion of chromium , the corrosion resistance of the steel in particular, decreased resistance to intergranular corrosion . Therefore . New developments since the 1960s, chrome-nickel austenitic stainless steel is mostly carbon content less than 0.03 %, or 0.02% of ultra-low carbon type, you can know as reduce the carbon content of the steel to intergranular corrosion susceptibility decreases when the carbon content of less than 0.02% it has the most significant effect, some experimental pearl also noted that carbon will increase chrome pitting corrosion of austenitic stainless steel tendencies. Because of the harmful effects of carbon , not only in austenitic stainless steel smelting over and shall be required to control the carbon content as low as possible , and in the subsequent heat, cold and heat treatment process is also to prevent the stainless steel surface by carbon , and chromium carbide precipitation . ======================== 【Article is excerpted from: Web Search】 【Reserved Integrate / Just Reference】 【Translation is by The Network】 |
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