|Hot forming temperature °C 1100 900
Annealing temperature °C 780 840
Hardening temperature °C 1000 1050
Tempering temperature °C 100 300
|Structure after Heat treatment||Condition||Product||Size mm||Hardness (average values) HB/HV|
|Ferrite + Carbide||≤||max. 285|
|Martensite + Carbide||ca. 61 HRC|
|Martensite + Carbide||hardened
for obtaining high hardness
|57 60 HRC|
|Physical properties at ambient temperature (average values):|
Modulus of elasticity
103 N/mm2, at...°C
Mean coefficient of thermal expansion between 20°C and ...°C, 10 (m/(m.K)
|Chemical composition (%)|
|0,95-1,20||≤ 1,00||≤ 1,00||≤ 0,040||≤ 0,030||16,00-18,00||≤ 0,75|
Additional Technical Information for 1.4125 / 440c:
|Mechanical Properties above ambient temperature:|
Condition: Hardened & Tempered
Coeffecient of Thermal Expansion between 20ºC and...
|Temperature ºC||Coefficient (10-6 K-1)|
|Physical properties at 20°C|
|Density||Specific Heat||Heat Conduction||Electrical Resistance||Modulus of Elasticity||Magnetic||Polishable||Weldable|
440c Martensitic Stainless Steel
This material will achieve the highest hardness of the available hardenable stainless steels. It possesses good corrosion resistance, particularly in the hardened and tempered condition. The material is magnetic in all conditions.
Heat Treatment Practice
In order to achieve the optimum properties for this material, it is imperative that the correct heat treatment is carried out in accordance with the following recommendations:
Normalising is not recommended
Annealing may be required on material in the as forged condition in order to aid machining prior to hardening and tempering. Annealing should be carried out under vacuum conditions to avoid surface decarburisation.
- Annealing: Process anneal 675ºC - 760ºC
- Full anneal 845ºC - 900ºC
- Hardness achievable: 23/25 HRc
- Note: The material supplied by Intoco is already in the annealed condition unless otherwise stated.
Hardening should be carried out under vacuum conditions to avoid surface decarburisation and to maintain a clean bright product.
Preheat 760ºC - 800ºC
Austenitise 1010ºC - 1065ºC
Nitrogen gas quench 2 - 6 bar overpressure
As quenched hardness 60/62 HRc
The upper end of the temperature range should be used for larger sections or when maximum corrosion resistance and strength are required. Similarly the greater quench pressure should be used in order to maximise these properties.
Sub Zero treatment
For minimum retained austinite and maximum dimensional stability, parts should be sub-zero treated between -70º / -80ºC.
This should be carried out immediately after hardening once the parts have reached ambient temperature.
Tempering should be carried out depending on properties required, in all cases double tempering is recommended.
165ºC for maximum hardness 60 HRc
190ºC - 230ºC for a combination of hardness & toughness 56/58 HRc
350ºC for maximum toughness 52/54 HRc
To further enhance surface characteristics, post heat treatment nitriding may be carried out on this material. Typical depth achieved being 0.008/0.010"
Please note the above specification has been provided by and is the responsibility of the TTI Group Limited. This information is provided to further the possibilities to our customers. You must satisfy yourselves that this specification meets the criteria for your products.