introduction of metal materials
metal materials are most widely used in our daily lives and industrial uses.there are several categories of metal materials including steel, iron ,nonferrous material etc.and steel is the most commonly used among them. iron is the main element in steels,other elements including all kinds alloy elements added and foreign elements.the vast varieties in the properties of steel are due to the differences of these alloy elements regarding categories and percentage.such as ordinary carbon steel ,stainless steel, alloy steel etc.carbon is playing an indispensable role in the functioning of the alloy elements.
iron makes up the majority percentage in all kinds of steels.several alloy elements can be mostly seen in the steel such as carbon(c),silicon (si), manganese(mn),phosphorus(p),sulfur(s),chromium(cr),nickel(ni),molybdenum(mo),titanium(ti) ,vanadium(va) etc.
often we see phosphorus and sulfur as foreign substances,the less percentage these two elements make up the higher quality the steels are.
steel can be simply classified into three categories in accordance with the alloy elements added to it as: carbon steel,alloy steel, stainless steel.carbon steel is the kind with only the alloy elements of c,si, mn,p,s,and can be categorized according to the percentage p and s are making up as :ordinary carbon steel(p and s each less than 0.04%) like:Q215A, Q235BF and high quality carbon steel(p and s each less than 0.03%) like:20#,45#,16Mn etc.alloy steel also contains elements cr,mo,v with less than ten percent in addition to the five ordinary elements above mentioned.
stainless steel:with a as high as 20 percent percentage of alloy such as cr,ni,etc added.
for example:
in japan and the united states:304(C<0.08%； Cr~18%； Ni~9%) 316(304 + Mo(~2.5%)
in china0Cr18Ni9(C≤0.08%；Cr~18%；Ni~9%)
L360:pipe steel,L is the symbol of tensile strength .so here the meaning is tensile strength 360mpa .it is mainly used for spiral-welding pressure pipeline with elements :0.08～0.12C, 0.10～0.25Si, 1.10～1.30Mn, ≤0.015P, ≤0.008S, 0.03～0.05Nb.models such as: L360QS seamless steel pipe and L360MS longitudinal submerged arc welding pipe.
deformation method:uoe is a physical deformation method to produce steel pipes from the steel plates.
20G:(changed to Q245R in 2008)one kind of steel .mainly used in vessels.G is the first letter of the word vessel spoken in mandarin as”guo “ specification should be referred to as”GB713-1997,applicable extent :steel plates with the thickness from 6mm to 150mm.nondestructive testing is in accordance with JB/T4730.3-2005(including three different degrees).
20G mechanical properties: tensile strength:410-550 mpa. yield strength:235-245mpa .elongation:20%
the difference between20# and 20G except sharing the same carbon content:some rare elements are contained in 20G which better the steel to be used in pressure vessels.and 20G is often judged by its mechanical properties like:bend,impact and tensile strengths.
20# steel:C—(0.17～0.24)% Si—(0.17～0.37)% Mn—(0.35～0.65)% P—≤0.040% S—≤0.040%.mechanical properties:yield strength:more than 250mpa,tensile strength:more than 420mpa,elongation:more than 25%,reduction of area:more than 55%,impact toughness:none,hardness:156HBS under the condition of hot rolling.
16mn: mainly used as forges,chemical compositionC ：0.13～0.19 Si :0.20～0.60 Mn :1.20～1.60 Cr ≤0.30 P≤0.030 S≤0.020 Ni≤0.30 Cu≤0.25
forged 16mn mechanical properties:nominal wall thickness:less than 300mm.heat treatment :nominalizing then tempering with the tempering temperature over 600 celsius.
mechanical properties:tensile strength:450-600mpa ,yield strength:over 275mpa ,elongation:20%.impact test:test temperature:0 celsius.impact toughness:over 31 , brinell hardness:from 121 to 178
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