Fe, <0.15%C, 16-18%Cr, 6-8%Ni, <2%Mn, <1%Si, <0.045%P, <0.03%S

Background

Grade 301 can be supplied with a tensile strength of up to 1800 MPa in strip and wire forms, to produce tempers in the range of 1/16 Hard to Full Hard. The controlled analysis of Grade 301 enables it to retain sufficient ductility in conditions up to 1/2 hard conditions to be roll or brake formed into aircraft, architectural and particularly rail car structural components. However, 3/4 to full hard tempers should be used whenever high wear resistance and spring features are required in components of simple form designs. Grade 301L with low carbon is preferred for improved ductility, and another variant 301LN with higher nitrogen content has a higher work hardening rate than standard 301. Only Grade 301 is specified in ASTM A666, but 301L is covered by JIS G4305 and 301LN is in EN10088-2 as grade 1.4318.

Key Properties

The properties for Grade 301 are specified for flat rolled product (plate, sheet and coil) in ASTM A666. Similar but not identical mechanical properties are specified in EN 10088.2 and JIS G4305 and in proprietary specifications. Composition Typical compositional ranges for grade 301 stainless steels are given in table 1. Table 1. Composition ranges for 301 grade stainless steel Grade C Mn Si P S Cr Mo Ni N 301 ASTM A666 min. max. - 0.15 - 2.0 - 1.0 - 0.045 - 0.030 16.0 18.0 - 6.0 8.0 - 0.10 301L JIS G4305 min. max. - 0.03 - 2.0 - 1.0 - 0.045 - 0.030 16.0 18.0 - 6.0 8.0 - 0.20 1.4318/301LN EN 10088-2 min. max. - 0.03 - 2.0 - 1.0 - 0.045 - 0.015 16.5 18.5 - 6.0 8.0 0.10 0.20 Mechanical Properties Typical mechanical properties for grade 301 stainless steels are given in table 2. Table 2. Mechanical properties of 301 grade stainless steel Grade 301 Temper ASTM A666 Tensile Strength (MPa) min. Yield Strength 0.2% Proof (MPa) min. Elongation (% in 50mm) (thick.>0.76mm) min. Bend Test (thickness > 1.27mm) Bend Angle (°) Factor Annealed 515 205 40 - - 1/16 Hard 620 310 40 180 1 1/8 Hard 690 380 40 180 1 1/4 Hard 860 515 25 90 2 1/2 Hard 1035 760 18 90 2 3/4 Hard 1205 930 12 90 3 Full Hard 1275 965 9 90 5 Bend test is around a diameter of the Bend Factor multiplied by the steel thickness. Physical Properties Typical physical properties for grade 301 stainless steels are given in table 3. Table 3. Physical properties of 301 grade stainless steel Grade Density (kg/m3) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (mm/m/°C) Thermal Conductivity (W/m.K) Specific Heat 0-100°C (J/kg.K) Electrical Resistivity (nW.m) 0-100°C 0-315°C 0-538°C at 100°C at 500°C 301 8000 193 17.0 17.2 18.2 16.2 21.5 500 720 Grade Specification Comparison Approximate grade comparisons for 301 stainless steels are given in table 4. Table 4. Grade specifications for 301 grade stainless steel Grade UNS No Old British Euronorm Swedish SS Japanese JIS BS En No Name 301 S30100 301S21 - 1.4310 X10CrNi18-8 2331 SUS 301 These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted. Possible Alternative Grades Possible alternative grades to grade 301 stainless steels are given in table 5. Table 5. Possible alternative grades to 301 grade stainless steel Grade Why it might be chosen instead of 301 304 The lower work hardening rate of 304 is acceptable, giving better ductility required for forming. 316 A higher corrosion resistance is required, and the lower work hardening rate of 316 can be compensated for. Corrosion Resistance Corrosion resistance is similar to that of 304. Good resistance in applications involving external exposure to mildly corrosive conditions at ambient temperatures. Heat Resistance Good oxidation resistance in intermittent service to 840°C and in continuous service to 900°C, although not usually chosen for this environment. Heat Treatment Solution Treatment (Annealing) - Heat to 1010-1120°C and cool rapidly. Use low side of range for intermediate annealing. This grade cannot be hardened by thermal treatment. Cold Working Grade 301 and its low carbon variants are used where a high strength stainless steel is required. The grades work harden at the very high rate of approximately 14MPa/%Ra (14MPa increase in tensile strength for each 1% reduction of area of cold work), resulting in high achievable strengths from cold rolling and from roll forming. The strain-hardened austenite is at least partially transformed to martensite by this work. Despite the high strengths achieved there is still enough residual ductility to enable severe cold deformation. Although non-magnetic in the annealed condition, when cold worked the grade becomes strongly attracted to a magnet. Welding Good characteristics suited to all standard methods. Grade 308L filler rod is recommended. Welds in Grade 301 must be annealed for maximum corrosion resistance; this is not necessary in 301L or 301LN. Welding and post weld annealing will both remove high strength induced by prior cold rolling. Spot welding is commonly used to assemble cold rolled 301 components. The very small heat affected zone associated with this rapid welding technique results in little reduction of overall component strength.

Applications Typical applications include: · Rail car structural components - often roll formed, brake pressed or stretch formed to profiles but also used flat. · Airframe sections · Highway trailer components · Automotive wheel covers · Wiper blade holders and clips · Toaster springs · Stove element clips · Screen frames · Curtain walls