CK45 Carbon Steel | DIN 1.1191-SEW550

CK45 steel, with an average carbon content of 0.45%, is classified as medium carbon steel, which is one of the most widely used non-alloy carbon steels in German standards.

Similar to American Standard 1045 steel, CK45 steel has good tensile properties and machinability, so it is widely used in the field of machinery manufacturing.

CK45 Steel can be formed by hot rolling and forging, and is generally supplied in an untreated or normalized condition.Through further heat treatment (such as quenching and tempering), the comprehensive properties of C45 steel can be improved.

C45 Forged steel with Normalized condition

CK45 STEEL CHEMICAL COMPOSITION

Standard	Grade	C	Si	Mn	P	S
SEW550	CK45/1.1191	0.42-0.50	≤0.35	0.50-0.80	≤0.035	≤0.035
DIN 17200	CK45/1.1191	0.42-0.50	≤0.4	0.50-0.80	≤0.035	≤0.03

CK45 STEEL RELATED STANDARD & EQUIVALENT GRADE

CHINA | GB 3077:45#

USA | ASTM A29: 1045

JAPAN | JIS G4051:S45C

Europe | EN10083:C45

UK | BS970:EN8/080M40

What is the Difference Between CK45 and C45E Steel?

CK45 grades come from early German standards, such as SEW550 and DIN17200, while C45E comes from 21st century European standards, such as EN10083 and EN10250. They share the number code 1.1191, so it can be said that C45E replaced CK45, but CK45 is still used now.

Standard	Grade	C	Si	Mn	P	S	Cr	Ni	Mo
SEW550	CK45/1.1191	0.42-0.50	≤0.35	0.50-0.80	≤0.035	≤0.035	-	-	-
DIN 17200	CK45/1.1191	0.42-0.50	≤0.04	0.50-0.80	≤0.035	≤0.03	-	-	-
EN10083	C45E/1.1191	0.42-0.50	≤0.04	0.50-0.80	≤0.03	≤0.035	≤0.4	≤0.4	≤0.1
EN10250	C45E/1.1191	0.42-0.50	≤0.04	0.50-0.80	≤0.035	≤0.035	≤0.4	≤0.4	≤0.1

It can be seen from the above table that both CK45 and C45E are high-quality steels, and they have strict control over the harmful elements of sulfur and phosphorus. In particular, C45E puts forward higher requirements for the control of residual alloy elements Cr, Ni, and Mo.

CK45 STEEL FORGING

Initial Forging Temperature：1200℃
Final Forging Temperature：800℃
Heating Rate:Strictly control the heating speed, which should be uniform and stable to prevent cracking caused by improper heating.
Forging Ratio：above 4:1
Post-Forging Treatment:CK45 steel should be slowly cooling after forged.

CK45 STEEL HEAT TREATMENT

Temperature Selection for Different Types of Heat treatment for CK45 Steel

Soft Annealing:650 – 700°C,Cooling in furnace,hardness below 207 HBW
Normalizing:840-870°C
Water Quenching:820-850°C
Oil Quenching:830-860°C
Tempering:540-680°C

Jominy Quenching Test Curve For CK45 Steel

CK45 steel Jominy Quenching Test Curve

Quenching at 850°C

X:Distance from quenched end,in mm

Y:Hardness,HRC

Distance from quenched end mm		1	2	3	4	5	6	7	8	9	10	11	13	15	20	25	30
CK45	HRC Max	62	61	61	60	57	51	44	37	34	33	32	31	30	29	28	27
CK45	HRC Min	55	51	37	30	28	27	26	25	24	23	22	21	20	-	-	-

Guideline value Curve for CK45 Steel Mechanical Property

CK45 steel Mechanical property reference curve

X:Tempering temperature,^oC

Y:Tensile and Yield Strength,Mpa

Z:Elongation and Reduction in area,%

CK45 Steel Mechanical Property at 20^oC for Forged parts in Normalized condition

Diameter mm	≤250	250-500	500-1000
Tensile Strength Mpa	590-720	590-720	590-720
Yield Strength Mpa	≥325	≥305	≥295
Elongation %	L:≥18 T:≥14	L:≥16 T:≥13	L:≥15 T:≥12
Impact Charpy J	L:≥31 T:≥24	L:≥27 T:≥21	L:≥24 T:≥17