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Alloy 255 Stainless Steel

UNS S32550

Description

255

STAINLESS STEEL

Alloy 255 is a super duplex stainless steel which includes 25% chromium. As a 25% Cr alloy, with significant additions of copper, it offers excellent corrosion resistance in a wide variety of corrosive chemicals including sulphuric, nitric and phosphoric acid. In seawater and other chloride containing environments, it also provides outstanding resistance to pitting and crevice corrosion, with critical pitting temperature exceeding 50 °C. In addition, alloy 255 has great ductility and impact strength at both ambient and sub-zero temperatures. Alloy 255 has been used in the chemical processing, marine and oil industry for applications such as valves, pipes, vessels, shaft seals and pumps.

Chemical Component

Cr	Ni	Cu	Mo	Si	C	Mn	S	N	P
24.0-27.0%	4.5-6.5%	1.50-2.50%	2.9-3.9%	1.0%	0.04%	1.50% max	0.03%	0.10-0.25%	0.04%

Basic Information

Items	Alloy 255 Stainless Steel	Temperature
Catalog	ACMA-Fe-A053	-
Density	7.81 g/cm³	Room
Specific Heat	0.113 Kcal/kg.C	20 °C
Melting Range	1385 - 1443.3 °C	-
Modulus of Elasticity	199 KN/mm²	20 °C
Electrical Resistivity	78.6 µΩ·cm	20 °C
Coefficient of Expansion	11.1 µm/m °C	20 °C-100 °C
Thermal Conductivity	14.2 W/m-°K	20 °C

Material Forms

Alfa Chemistry offers alloy 255 stainless steel in a variety of forms, including Pipes, Tubes, Bars, Sheets, Plates, Wires.

Mechanical Properties

Ultimate Tensile Strength	Yield Strength (0.2% offset)	Elongation in 2 inches
110 KSI	80 KSI min	30%

Additional Properties

Machining: Albeit generously harder than most different stainless steels, alloy 255 can be effectively machined utilizing most common techniques. Slow speeds and heavy, steady feeds are required to overcome this alloy's tendency to work harden.
Forming: Alloy 255 can be effectively formed utilizing each and every technique of hot or cold working.
Welding: Alloy 255 can be effectively welded utilizing most common technique, including GTAW, GMAW and SMAW process. At the point when this filler metal is required, for joining with a disparate of higher alloy content, select the filler relating to the higher alloy material for best results.
Heat Treatment: The alloy reacts to annealing, yet is not age-hardenable.
Hot Working: Forging might be done within the scope of 2220 °F to 1700 °F. A re-anneal must be done following forging in order to regain optimum corrosion resistance.
Cold Working: This is a ductile alloy, like the stainless steels yet stiffer and it is promptly cold worked by standard means. Annealing must be done after cold work to restore corrosion resistance.
Annealing: Anneal at 1900 °F and fast cool.
Hardening: Hardens are done by cold work only, but should be utilized in annealed condition for corrosion resistance.

Specifications

Bar: ASME SA 479, ASTM A479, ASTM A276

Sheets and Plates: ASTM A240, ASME A240

Pipe: ASTM A789, ASTM A790, ASME A789, ASME A790

Tube: ASTM A789, ASTM A790

Features

Superior corrosion resistance
Pitting
Crevice corrosion
Chloride stress corrosion cracking
General corrosion in many environments
Good ductility

High strength-to-weight ratio
High fatigue strength in marine environments
Superior abrasion and cavitation erosion resistance
High mechanical strength-(over twice the yield strength of austenitic stainless steels)
Good fabricability

Applications

Chemical process industry
Marine industry and shipbuilding
Oil and gas industry
Pollution control
Copper smelting

Pulp and paper industry
Food industry
Agrochemicals
Civil engineering

* Technical data included herein should be used as a guideline only, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice.

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Alfa Chemistry is a manufacturer of standard & custom specialty metals & alloys. We stock a wide variety of alloys in different shapes and specifications. If you can't find the product or specification you need, please contact us directly.