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Screws Index Page...

Tensile and Proof Stress Of Metric Bolts and Screws. (Carbon Steel )

Indicated stresses in Newton/mm²

Strength Designation	3.6	4.6	4.8	5.6	5.8	6.8	8.8 =< 16mm	8.8 > 16	9.8	10.9	12.9
Nom. Tensile Strength	300	400	400	500	500	600	800	800	900	1000	1200
Min Tensile Strength	330	400	420	500	520	600	800	830	900	1000	1200
Lower Yield Stress	180/190	240	320/340	300	400/420	480	-	-	-	-	-
Stress at Perm. Set	-	-	-	-	-	-	640	640/660	720	900/940	1080/100

In accordance with BS 3692:2001 and BS EN IOS 898-1 : 1999

Tensile Strength Of Metric Nuts

Indicated stresses in Newton/mm²

Strength Designation	4	5	6	8	10	12
Tensile Strength	400	500	600	800	1000	1200

In accordance with BS 3692:2001

The designation system allows the determination of the ultimate and yield/proof strength of the bolt. The designation system is based on two numbers e.g 8.8 .  The first number is the tensile strength of the bolt material (N² )/100.  The second number is = 1/100.(the ratio of the Proof (or Yield ) stress and the Tensile strength expressed as a percentage = 100.[Yield (Proof stress) /Tensile strength] /100

The tensile and proof strength of the steel for a 4.6 bolt is therefore calculated as follows

Tensile strength (R_m) = 4.100 N/mm² = 400 N/mm² .... Proof strength (R_0,2) = 0,6*400 * 100 /100 = 240 N/mm²

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Tensile and Proof Stress Of Metric Bolts and Screws. (Stainless Steel )

Stainless steels include Austenitic, Martensitic and Ferritic..

Austenitic stainless steels..
Chromium nickel steels which can be cold worked. Non magnetic.
Associated grades ( Steel Number according to BS EN 10088 pt 1) = A1 (1.4305) , A2 (1.4301) ,A3 (1.4541) , A4 (1.4401) and A5 (1.4571).

Martensitic stainless steels ..
Limited corrosion resistance but can be heat treated for superior strength properties. Magnetic Properties.
Associated grades ( Steel Number according to BS EN 10088 pt 1) = C1 (1.4006 etc) , C3 (1.4057), C4(1.4104)

Ferritic stainless steels ..
Plain chromium stainless steels with a chromium content varying between 10.5 and 18% and a low carbon content. They not hardenable by heat treatment. Ferritic alloys have good ductility and formability but a relatively poor high temperature strength compared austenitic grades. Magnetic..
Associated grades = F1

Tensile and Proof Stress Of Metric Bolts and Screws. (Stainless Steel )

Indicated stresses in Newton/mm²

Stainless Steel	Austenitic				Martensitic				Ferritic
Steel Grade	A1, A2, A3, A4, A5				C1,C4		C1	C3	F1
Strength class	50	70	80	100	50	70	110	80	45	60
Tensile Strength	500	700	800	1000	500	700	1100	800	450	600
0,2% proof stress	210	450	600	750	250	410	820	640	250	410

Relevant Links Boltscience bolt strength..Detailed notes Screw strength calculator..short 1 page informatin sheet with calculator

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