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The analysis of Type 304 is similar to that of Type 302, except that Type 304 is modified by lowered carbon content This provides good resistance to corrosion in welded construction where subsequent heat treatment is not practicable. Bars and Plates are available not only in the regular Type 302 and 304 analyses, but also in an extra low carbon analysis, known as Type 304L. The advantage of this analysis is that it precludes any harmful precipitation in the 800°-1500°F range, such as might otherwise occur in welding heavier sections.

UNS S30200. S30400, S30403

Physical Condition A

Stock Lengths 10' to 12'
Unit of Measure

Specifications

Estimated Weight per Foot

N/A 26.53 lb

Estimated Weight 12-Ft. Bar

N/A 318.3 lb

Analysis

N/A 304
Carbon .08 Max.
Manganese 2.00 Max.
Phosphorus .040 Max.
Sulphur .030 Max.
Si. 1.00 Max.
Cr.18.00/20.00
Ni. 8.00/10.50
Cu. .75 Max.
Mo. .75 Max.

Specifications

N/A The following specifications are generally applicable:
Sheets & Plates: MIL-S-5059, AMS 5513, ASTM A 167, ASTM A 240
Bars: MIL-S-7720, QQ-S-763, AMS 5639, ASTM A 276, ASTM A 479

Applications

N/A Used where corrosion resistance and good mechanical properties are primary requirements. These grades are widely accepted in such industries as dairy, beverage, and other food products where the highest degree of sanitation and cleanliness is of prime importance. Parts for handling acetic, nitric, and citric acids, organic and inorganic chemicals, dyestuffs, crude and refined oils, etc., are fabricated from this material. Because of its lack of magnetism it is highly desirable for instruments. It is also widely used for architectural trim. Type 302 sheets are used in aircraft applications where corrosion resistance is required, but where gas or arc welding and elevated temperatures are not involved. Type 304, as noted above, finds particular use in applications requiring welding.

Corrosion Resistance

N/A Types 302 and 304 show good resistance to corrosion. They are highly resistant to strong oxidizing acids, such as nitric acid, and resist attack by a wide variety of organic and inorganic chemicals. Maximum corrosion resistance is obtained in the annealed condition. Intergranular corrosion may occur when material is heated within or cooled through the range of 800° to 1500°F.

Resistance to Scaling

N/A Excellent scale resistance at temperatures up to 1600°F in continuous service. Chromium-nickel grades have a high coefficient of expansion, which should be considered in designing.

Mechanical Properties

N/A Applicable specifications require the following properties of sheets in the annealed condition:
304
Tensile Strength - 100.00 psi Max.
Elongation in 2"( 0.15" Thick and Under) - 40% Min.
Elongation in 2"( 0.16" Thick to .030") - 40% Min.
Elongation in 2"( 0.031" Thick and Over) - 40% Min.
Elongation in 2" - 17% Min.
In practice, annealed sheets and plates will average as follows:
Tensile Strength - 90.00 psi
Yield Strength - 40,000 psiMin.
Elongation in 2" - 50% Min.
Rockwell "B" Hardness 85.0

Machinability

N/A Types 302 and 304 have a machinability rating of approximately 45% with 1212 rated as 100%. Surface cutting speed on automatic screw machines is approximately 75 feet per minute.

Weldability

N/A Easily welded by all the commercial processes except forge or hammer welding. The resulting weld has good toughness and ductility. Annealing is recommended after welding to maintain maximum corrosion resistance.

Forming

N/A These grades have very good drawing and stamping properties.

Forging

N/A Forge between 2100° and 2350°F. Do not forge below 1700°F

Annealing

N/A Annealing range is between 1850° and 2050°F. Cool rapidly
Water should be used for heavier sections; air for lighter sections.
The stress relieving range is between 400° and 750 °F.