Overview
439 steel is based on the ordinary ferritic material (430) to reduce the content of Carton, while adding Ti and other stabilizing elements, so that the steel resistance to intergranular corrosion, formability and weldability have been improved. Compared with 304 steel, although the elongation is low (about 30%), the strength and corrosion resistance are comparable, and the corrosion resistance is better than that of 200 series materials. 439 stainless steel is a stable ferritic stainless steel (chromium content 17.0 min, max 19.0 max). Its chromium (Cr) content is higher than that of 409 stainless steel, thus improving corrosion resistance. 439 stainless steel is stabilized by the addition of titanium (Ti), thus having good weldability. The alloy resists intergranular corrosion and stress corrosion cracking. Compared to SUS304, it has higher thermal conductivity and lower coefficient of expansion. Commonly used in automotive exhaust components, heat exchanger piping, kitchen equipment, household appliances and building structure applications.
Application
Elevator, escalator decorative board architectural decorative board, such as decorative structural parts, structural tubes, automotive exhaust system components, washing machine inner cylinder.
Equivalent Standards
| AISI | DIN | UNS |
| 439 | 1.451 | S43036 |
439 Stainless Pipe Chemical Composition
| Carbon | 0.030 max. |
| Manganese | 1.00 max. |
| Sulfur | 0.030 max. |
| Phosphorus | 0.040 max. |
| Silicon | 1.00 max. |
| Chromium | 17.0 – 19.0 |
| Nickel | 0.50 max. |
| Nitrogen | 0.030 max. |
| Aluminum | 0.15 max. |
| Titanium | [0.20+4x(C+N)] min. – 0.75 max. |
Physical Properties
| Melting Point | 2741°F (1505°C) |
| Density | 0.278 lbs/in3 / 7.70 g/cm3 |
| Modulus of Elasticity in Tension | 28 X 106 psi / 193 GPa |
Mechanical Properties
| Tensile Strength Minimum (psi) | 66,000 - 70,000 |
| Yield Strength Minimum 0.2% offset (psi) | 43,000 - 48,000 |
| % Elongation in 2” Minimum | 32 - 36% |
| Hardness | Rockwell B74 - 78 |
Heat Treatments: Type 439 is not hardenable by heat treatment
Annealing:Heat slowly to 1450 -1600°F (790 - 871°C), quickly cool. Slow cooling produces less desirable impact transition behavior. Ferritic stainless steels containing more than about 12% chromium have a susceptibility to a phenomenon known as 885°F (475°C) embrittlement. This embrittlement is observed as a degradation of impact properties at room temperature resulting from very long exposures in the temperature range of 700 to 1000°F (371 to 537°C). If service temperatures are cycling through this range, exposure above, about 1050°F (565°C), restores the room temperature toughness properties. When there have been long dwell times near 885°F (475°C), service temperatures that cycle above, about 1050°F (565°C), are beneficial rather than detrimental.
Corrosion Resistance
AISI Type 439 is resistant to attack by potable water and many mildly or moderately corrosive chemical environments which are oxidizing in nature. In various chloride solutions, studies have shown pitting resistance of Type 439 to be superior to that of Type 304. In addition, Type 439 is not subject to stress corrosion cracking which may cause premature failure of austenitic steels in chloride bearing environments such as hot waters used in heat exchangers.
Package Process
1.with plastic cap to protect both ends
2.weaving bag wrapped outside the pipe
3.then pack into wooden case.
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AISI 439 Stainless Steel Seamless Round Tubes Cold Rolled SS 2" Sch Xxs Images
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