Non-Water-Hardenable Steels
C55E – 1.1203 / 1055 / Ck55 / S55C / XC54 / 070M55 / C55 / C55k / F1150 / 55 / C55E4
C55E – 1.1203 steel grade belongs to the group of medium-carbon structural steels and is widely used in applications requiring high strength and hardness. Although it is identified by different names across various international standards, its fundamental properties remain largely consistent. For example, it is known as C55E – 1.1203 in Europe, AISI 1055 in the United States, Ck55 in Germany, S55C in Japan, XC54 in France, and 070M55 in the United Kingdom. These alternative designations demonstrate the steel’s broad global use in engineering and manufacturing industries.
C55E steel typically contains approximately 0.52% – 0.60% carbon. This carbon content provides the material with high strength and hardness, while offering lower ductility compared to low-carbon steels. For this reason, it is particularly suitable for applications where strength and wear resistance are critical.
One of the key advantages of C55E steel is its excellent response to heat treatment processes. Through hardening and tempering, the mechanical properties of the material can be significantly improved. Hardening increases the surface and overall hardness, while tempering reduces brittleness and ensures a more balanced mechanical structure. In addition, induction surface hardening can be applied to improve surface durability while maintaining a tough core.
C55E steel is especially suitable for mechanical components subjected to medium and high loads. It is widely used in machine manufacturing, the automotive industry, and various industrial applications, where it provides durable and long-lasting performance. Its machinability is moderate, and it is typically processed using turning, milling, and grinding operations.
Offering a well-balanced combination of strength, hardness, and heat treatment capability, C55E – 1.1203 steel stands out as a reliable material for performance-oriented applications. Its cost-effectiveness and wide availability further contribute to its widespread use.
Main Application Areas
- Production of shafts, axles, and spindles
- Gears, pinions, and transmission components
- Springs and elastic machine elements
- Wear-resistant mechanical components
- Various mechanical parts in the automotive industry
- Durable components used in agricultural machinery
- Parts suitable for induction surface hardening
- Medium and high load-bearing structural elements
- Various tools and machine components
Thanks to these characteristics, C55E – 1.1203 and equivalent steel grades are widely used as important engineering materials in industrial applications requiring high strength and long service life.
General Identity
C55E – 1.1203
| Grade |
C55E |
| Number |
1.1203 |
| Classification |
Special Steel |
Equivalent Grades
C55E – 1.1203
| USA |
1055 |
| Germany, DIN |
Ck55 |
| Japan, Jis |
S55C |
| France, AFNOR |
XC54 XC55H1 |
| England, BS |
070M55 |
| Italy, UNI |
C55 |
| Spain, UNE |
C55k F1150 |
| Russia, Gost |
55 |
| Inter, ISO |
C55E4 |
Standards
C55E – 1.1203
| Standard 1 |
EN 10083-2: 2006 |
| Standard 2 |
EN 10132-3: 2000 |
| Standard 3 |
EN 10250-2: 2000 |
Chemical Composition
C55E – 1.1203
| C |
0.52 – 0.66 |
| Si |
max 0.40 |
| Mn |
0.60 – 0.90 |
| Ni |
max 0.40 |
| P |
max 0.030 |
| S |
max 0.035 |
| Cr |
max 0.40 |
| Mo |
max 0.10 |
Mechanical Properties
C55E – 1.1203
| Nominal thickness (mm) |
to 16 |
16 – 100 |
100 – 250 |
250 – 500 |
500 – 1000 |
| Rm – Tensile strength (MPa) (+N) |
680 |
640 |
620 |
600 |
590 |
| Nominal thickness (mm) |
0.3 – 3 |
| Rm – Tensile strength (MPa) (+A) |
600 |
| Nominal thickness (mm) |
0.3 – 3 |
| Rm – Tensile strength (MPa) (+QT) |
1100 – 1700 |
C55E – 1.1203
| Nominal thickness (mm) |
tp 16 |
16 – 100 |
100 – 250 |
250 – 500 |
500 – 1000 |
Re – Upper yield strength or
Rp0.2 – 0.2% proof strength (MPa) (+N) |
370 |
330 |
300 |
260 |
250 |
| Nominal thickness (mm): |
0.3 – 3 |
| Rp0.2 0.2% proof strength (MPa) (+A) |
480 |
| Nominal thickness (mm): |
0.3 – 3 |
| A – Min. elongation Lo = 80 mm (%) (+A) |
17 |
C55E – 1.1203
| Nominal thickness (mm) |
to 16 |
16 – 100 |
100 – 250 |
| A – Min. elongation Lo = 5,65 √ So (%) (+N) |
11 |
12 |
12 |
C55E – 1.1203
| Birinel hardness (HBW) (+S): |
255 |
| Birinel hardness (HBW) (+A): |
229 |
| Vickers hardness (HV) (+A) |
185 |
| Vickers hardness (HV) (+CR) |
300 |
| Birinel hardness (HBW) (+QT): |
340 – 520 |
