Steel structure join is divided with bolt property social estate 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9 wait for more than 10 grade, among them 8.8 class and above bolt material are low carbon alloy steel or medium carbon steel character and classics heat treatment (quench, temper) , appellative for high strenth bolt, the others is appellative for common bolt. Grade of bolt property social estate has two shares number to comprise, the nominal tensile strength that shows bolt stuff respectively is worth and bend strong specific value. For example, property social estate the bolt of 4.6 class, its meaning is:
1, tensile strength of bolt material qualitative nominal amounts to 400MPa class;
2, ratio is the Qu Jiang with bolt qualitative material 0.6;
3, the nominal with bolt qualitative material succumbs intensity amounts to social estate of 400×0.6=240MPa class property bolt of 10.9 class high strenth, after its material passes heat treatment, can achieve:
1, tensile strength of bolt material qualitative nominal amounts to 1000MPa class;
2, ratio is the Qu Jiang with bolt qualitative material 0.9;
3, the nominal with bolt qualitative material succumbs intensity amounts to 1000×0.9=900MPa class
The meaning of bolt property social estate is the level with current international, the bolt of same function social estate, no matter its material is mixed the distinction of producing area, its function is identical, property social estate is chosen only on the design can. Intensity grade is alleged 8.8 class and 10.9 class are those who point to bolt fight cut stress grade to be 8.8GPa and 10.9Gpa
Nominal of 800N/MM2 of 8.8 nominal tensile strength succumbs intensity 640N/MM2
General bolt shows strength with "X.Y" ,
The tensile strength of X*100= this bolt,
X*100* (Y/10) of = this bolt succumb intensity
(because press label regulation: Succumb intensity / tensile strength =Y/10)
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Be like 4.8 class
Criterion of this bolt
Tensile strength is: 400MPa
Succumb intensity is: 400*8/10=320MPa
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Additional: Normally mark is stainless steel bolt A4-70, the appearance of A2-70, the meaning has an explanation additionally
Magnanimity
Unit of measurement of the length on current world basically has two kinds, one kind is metric, unit of measurement is rice (M) , centimeter (Cm) , millimeter (Mm) etc, in the southeast Asia such as Ou Zhou, our country and Japan the area is used more, another kind is imperial, unit of measurement basically is inch (Inch) , be equivalent to our country old the city that make inch, in the United States, Europe United States such as England the home is used more.
1, metric and metric: (10 into make)
1m =100 Cm=1000 Mm
2, imperial and metric: (8 into make)
1 inch of =8 flower divide ×25.4 =9.52 of ￠ of ￠ of 1 inch of =25.4 Mm 3/8
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