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Home Material GB /T 17107-1997
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Grade 55
Corresponding Standard GB /T 17107-1997
Structural Steel Grades And Mechanical Property For Forgings
Classification Carbon Steel
Properties Strength Hardness
55 Chemical Element Composition Content (%)
Component C Si Mn P S Cr Ni Cu
Minimum Value 0.52 0.17 0.5 - - - - -
Maximum Value 0.6 0.37 0.8 0.035 0.035 0.25 0.25 0.25
• High-quality steel——P≤0.035；S≤0.035；Cu≤0.3；Cr≤0.3；Ni≤0.3
• Extra-quality steel （Suffix A）——P≤0.025；S≤0.025；Cu≤0.25；Cr≤0.3；Ni≤0.3
• Special High-Quality Steel (Suffix E)——P≤0.025；S≤0.015；Cu≤0.25；Cr≤0.3；Ni≤0.3
• Cu is not more than 0.3% when smelting scrap steel
55 Mechanical Properties
diameter or thickness
d
mm		 Mark
Heat Treatment or Condition
Tensile Strength
σb
Mpa 		Yield Point
σs
Mpa 		Elongation or Extension Rate
δ
% 		Reduction of Area
ψ
% 		Hardness
HBW 		Impact Energy Absorption
KV2
J
d≤100 Sample Direction: Longitudinal Normalizing + tempering ≥645 ≥320 ≥12 ≥35 187~229 ≥23
100＜d≤300 Sample Direction: Longitudinal Normalizing + tempering ≥625 ≥310 ≥11 ≥28 187~229 ≥19
300＜d≤500 Sample Direction: Longitudinal Normalizing + tempering ≥610 ≥305 ≥10 ≥22 187~229 ≥19
• The forgings must be inspected for mechanical properties after performance heat treatment and before any surface treatment.
• After the samples are removed, no heat treatments that affect the mechanical properties or any processing that influences the test results shall be conducted.
• Mechanical property testing primarily evaluates the material\'s tensile strength, impact resistance, and hardness. When conducting tensile, impact, and hardness tests simultaneously, the hardness value is for reference only. Alternatively, one may choose to perform only one of the tensile, impact, or hardness tests.
1 Approximate Comparison Table High-Quality Carbon Structural Steel
China Taiwan, China Japan South Korea United States International Organization for Standardization Germany France Russia Sweden United Kingdom
GB ISC CNS JIS KS ASTM/AISI UNS ISO DIN EN/DIN W-Nr. NF EN/NF GOST SS BS EN/BS
55 U20552 S55C S55C SM55C 1055
(ASTM) 		G10550 C55E4 C55E
Ck55 		1.1203 C55E
XC55 		55 1665 C55E
070M55
2 Approximate Comparison Table High-Quality Carbon Structural Steel
China Japan United States International Organization for Standardization France Russia United Kingdom
GB JIS ASTM/AISI ISO NF EN/NF GOST BS EN/BS
55
(GB/T 699-1999) 		S55C 1055 C55
C55E4
C55M2
(ISO 630-1:1987) 		C55
XC55 		55 060A57
070M55
3 Approximate Comparison Table High-Quality Carbon Structural Steel
China Japan United States International Organization for Standardization European Standard
GB ISC JIS ASTM/AISI ISO EN Numerical Grade
55
(GB/T 699-2015) 		U20552 S55C
(JIS G4051:2005)
(JIS G3506:2004) 		1055
(ASTM A29/A29M:2005) 		C55E4
(ISO 683-18:1996) 		C55E
(EN 10083-1:1991+A1:1996)
(EN 10084:1998) 		1.1203
4 Approximate Comparison Table High-Quality Carbon Structural Steel
China Germany
GB DIN EN/DIN
55 CF53
55 Corresponding Standards(Same grade name, different standards)
1 GB /T 699-1999
55 U20552 55#
2 GB /T 699-2015
55 U20552
3 GOST 1050-1988
55
4 GB /T 17107-1997
55
5 GB /T 3078-2019
55 55#
6 GB /T 711-2017
55 55#
7 GB /T 13237-2013
55
8 GB 3522-1983
55

Note: The data is for reference only! If you have any questions, please fill out "I want to correct it"!