Crucible 174 SXR
Crucible 174 SXR is a premium quality precipitation- hardening stainless steel designed for use as rifle barrels. It is a modification of Crucible’s 17Cr-4Ni which offers substantially improved machinability without sacrificing toughness. Its excellent corrosion resistance approaches that of a 300 series austenitic stainless steel, while its high strength is characteristic of 400 series martensitic stainless steels. At similar hardness levels, Crucible 174 SXR offers greater toughness than either the 410 or the 416 stainless steels which are commonly used for rifle barrels.
Typical Chemistry
Carbon 0.02%
Chromium 15.25%
Nickel 4.80%
Copper 3.50%
Manganese 0.60%
Silicon 0.50%
Columbium + Tantalum 0.20%
Phosphorus 0.025%
Sulfur 0.02%
Nitrogen 0.015%
Iron Balance

Crucible 174 SXR is a precipitation-hardening stainless steel which is capable of high strength and high hardness after a relatively simple heat treatment. This grade is martensitic and therefore magnetic in both the solution treated and precipitation-hardened conditions. It has high resistance to crack propagation and its corrosion resistance is superior to the standard martensitic 12 Cr hardenable stainless steels. Because it is hardened by a single low-temperature precipitation-hardening heat treatment, scaling and distortion are virtually eliminated. This enables material to be finish machined to close tolerances prior to heat treatment.
    Crucible 174 SXR meets the industry specifications for 17Cr-4Ni. By closely controlling the chemical composition within the standard range, Crucible 174 SXR shows a significant improvement in ductility over standard 17Cr-4Ni in all conditions, but especially in the solution-treated condition. In addition, the steel is markedly tougher than conventional 17Cr-4Ni as measured by Charpy impact tests.
    Crucible 174 SXR barstock is normally supplied in the solution treated condition (Condition A) ready for fabrication and subsequent precipitation hardening by the customer. However, it can be supplied in any of the several hardened conditions (Condition H’s).

Grade
Typical
HRC
Typical
Charpy V-Notch

174 SXR (H 1025) 38 40 ft-lbs
174 SXR (H 1075) 36 43 ft-lbs
174 SXR (H 1150) 33 100 ft-lbs
410 40 35 ft-lbs
410 35 25 ft-lbs
410 30 70 ft-lbs
416 30 20 ft-lb

Solution Treatment: 1900°F, 30 minutes Air Cool or Oil Quench. (Material supplied in Condition A is in the solution treated condition. It does not require solution treatment prior to precipitation hardening.)
Precipitation Hardening: Material supplied in Condition A can be heat treated at different temperatures to develop a wide range of properties. A number of standard heat treatments have been developed:

Condition
Hardening
Temp. °F
Time
(hr.)
Cool
HRC

H1025
1025
4
Air
38
H1075
1075
4
Air
36
H1100
1100
4
Air
35
H1150
1150
4
Air
33
H1150M

1400
1150
2
4
Air
Air

28
Double
H1150
1150
1150
4
4
Air
Air

31

Note: Properties shown in this data sheet are typical values. Normal variations in chemistry and heat treatment may cause deviations from these values.