1.5918 – 17CrNi6-6
Case-hardening alloy steel with high core strength and a highly wear-resistant surface

Steel 1.5918 (17CrNi6-6) is an alloyed chromium-nickel case-hardening steel intended for highly stressed components that require a hard surface and a tough core. Due to its chromium and nickel content, it offers very good hardenability, high core strength, and good resistance to dynamic and fatigue loading.

Thanks to the combination of high surface hardness after carburizing, strength, and toughness, it is commonly used for gears, pinions, shafts, pins, and other heavily stressed machine parts.

Properties of 1.5918 steel

🛡️ Suitable for carburizing
After carburizing and subsequent quenching, it achieves a very hard surface layer while maintaining a tough core.

🔩 High core strength
The material is suitable for heavily mechanically stressed parts that must withstand high loads and impact.

⚙️ Very good hardenability
The Cr and Ni content ensures good mechanical properties even in larger cross-sections.

✨ Good wear resistance after heat treatment
The hard carburized surface significantly increases the service life of functional and friction surfaces.

🔧 Good core toughness
Suitable for components exposed to vibrations, shocks, and repeated loading.

🔥 Suitable for heat treatment
It is commonly used for carburizing, quenching, and low-temperature tempering according to the required component properties.

Chemical composition 1.5918 (17CrNi6-6)

Element	Content (%)
C	0.14 – 0.20
Si	≤ 0.40
Mn	0.50 – 0.90
Cr	1.40 – 1.70
Ni	1.40 – 1.70
P	≤ 0.025
S	≤ 0.035

Applications of 1.5918 steel

⚙️ Transmission and machine parts

• gears
• pinions
• shafts
• pins
• axles

🚗 Automotive and transport industry

• transmission components
• heavily stressed rotating parts
• components exposed to dynamic loading

🏭 General industrial use

• carburized machine components
• parts requiring a hard surface and a strong internal structure
• mechanical parts with long service life

🛡️ Parts requiring wear resistance

• friction and functional surfaces
• precision mechanical components
• components exposed to fatigue loading

These applications correspond to the classification of the material according to EN 10084 as a case-hardening steel and to its typical properties.

Heat treatment (approximate values)

Process	Temperature	Note
Carburizing	880 – 980 °C	depending on the medium and required case depth
Core quenching	830 – 870 °C	for double quenching
Surface quenching	780 – 820 °C	for double quenching
Direct / single quenching	820 – 860 °C	depending on part shape and section
Tempering	150 – 200 °C	approximately min. 1 hour

Mechanical properties

• Tensile strength: approx. 580 MPa in the annealed condition; in some processed conditions up to around 1200 MPa for small cross-sections
• Hardness: approx. 156 – 255 HB, depending on delivery and heat-treated condition
• Good hardenability
• High core strength
• Suitable for carburized and highly stressed components