303 stainless steel plate

303 Stainless Steel Plate



Product Description

303 Stainless Steel Plate

303 stainless steel plate

Grade 303 stainless steel plate represents the optimum in machinability among the austenitic stainless steels. It is primarily used when production involves extensive machining in automatic screw machines. Machinability Rating (compared to B1212) is approximately 78%.303 is also available as a “Ugima” Improved Machinability grade, with machinability even higher than that of the standard 303.

 

 

The sulphur addition which is responsible for the improved machining and galling characteristics of Grade 303 lowers its corrosion resistance to below that of Grade 304. As for other austenitic grades the structure gives 303 excellent toughness, although the sulphur in 303 reduces its toughness slightly.Grade 303Se (UNS S30323) has a selenium rather than sulphur addition, improving the hot and cold forming characteristics over those of 303 and providing a smoother machined surface finish. The machinability rate is also slightly reduced. Grade 303Se is not readily available in Australia.

 
Applications of 303 Stainless Steel Plate:

Typical compositional ranges for grade 303 stainless steels are given in table 1.
Table 1. Composition ranges for 303 grade stainless steel

 Grade  C  Mn  Si  P  S  Cr  Mo  Ni  Se
 303  min.
max.
 –
0.15
 –
2.00
 –
1.00
 –
0.20
 0.15
-
 17.0
19.0
 -  8.0
10.0
 -
 303Se  min.
max.
 –
0.15
 –
2.00
 –
1.00
 –
0.20
 0.06
-
 17.0
19.0
 - 8.0
10.0
0.15
min

Typical mechanical properties for grade 303 stainless steels are given in table 2.
Table 2. Mechanical properties of 303 grade stainless steel

 Grade  Tensile Strength (MPa)  Yield Strength 0.2% Proof (MPa)  Elongation (% in 50mm)  Hardness
 Rockwell B (HR B)  Brinell (HB)
 303  -  -  -  - 262 max

Typical physical properties for annealed grade 303 stainless steels are given in table 3.
Table 3. Physical properties of grade 303 stainless steel plate in the annealed condition

 Grade  Density (kg/m3)  Elastic Modulus (GPa)  Mean Coefficient of Thermal Expansion (μm/m/°C)  Thermal Conductivity (W/m.K)  Specific Heat 0-100°C (J/kg.K)  Electrical Resistivity (nΩ.m)
 0-100°C  0-315°C  0-538°C  at 100°C  at 500°C
 303  8027  193  17.3  17.8  18.4  16.3  21.5  500 720

Approximate grade comparisons for 303 stainless steels are given in table 4.

Table 4. Grade specifications for grade 303 stainless steel plate

 Grade  UNS No  Old British  Euronorm  Swedish SS  Japanese JIS
 BS  En  No  Name
 303  S30300  303S31 58M   1.4305  X8CrNiS18-9  2346  SUS 303
 303Se  S30323  303S42  -  -  - -  SUS 303Se

Possible alternative grades to grade 303 stainless steels are given in table 5.
Table 5. Possible alternative grades to 303 grade stainless steel

 Grade  Why it might be chosen instead of 303
 304  Better corrosion resistance, formability or weldability are needed, at the expense of lower machinability.
 316  Higher resistance to pitting and crevice corrosion is required, in chloride environments. A lower machinability can be accepted.
 416 Even higher machinability than 303 is needed, and a lower corrosion resistance can be tolerated.
Or hardening by thermal treatment is required, while maintaining a high machinability.