AM 355 / SUS 634 High Temperature Alloys Melting Range 2500 - 2550°F For Food Industry Parts

S35500 (AM 355, SUS 634) semi-product for food industry parts request high strength at intermediate elevated temperature

1 PRODUCT

UNS S35500 (AM 355, SUS 634) semi-products for food industrial parts requesting high strength at intermediate elevated temperatures.

UNS S35500 is available in product forms as plate, sheet, strip, pipe, tube, bar (round, flat, hexagon, square, shapes), wire (profile, round, flat, square), forgings, etc.

2 EQUIVALENT DESIGNATION

AM 355 (Type 634), AISI 355, Grade 355, SUS 634(JIS), CarTech® 355 Alloy (Pyromet alloy 355)

3 APPLICATION

S35500 has been used for gas turbine compressor components such as blades, discs, rotors and shafts, industrial cutters and similar parts where high strength is required at intermediate elevated temperatures.

4 OVERVIEW

S35500 is a chromium-nickel-molybdenum stainless steel which can be hardened by martensitic transformation and/or precipitation hardening.

Depending upon the heat treatment, S35500 may have an austenitic structure and formability similar to other austenitic stainless steels or a martensitic structure and high strength comparable to other martensitic stainless steels. High strengths may also be attained by cold working, and are maintained (whether produced by heat treatment or by cold work) at temperatures up to 1000°F (538°C). Corrosion resistance of the material is superior to that of other quench-hardenable martensitic stainless steels and approaches that of the chromium-nickel austenitic stainless steels.

The material is usually supplied in either the annealed or in the equalized and over-tempered condition.

5 CHEMICAL COMPOSITION (wt%):

6 PHYSICAL PROPERTY

Melting range: 2500-2550°F

Density:

Annealed: 7920 kg/m³(0.286 lb/in³)

Condition SCT 850 (Sub-zero Cooled, Tempered 850°F (454°C)): 7810 kg/m³(0.282 lb/in³)

Mean specific heat 32 to 212°F: 0.12 Btu/lb/°F

Mean coefficient of thermal expansion

Thermal conductivity

7 MECHANICAL PROPERTIES

Typical elevated temperature tensile properties of bar, sub-zero cooled, tempered

Typical room temperature mechanical properties, bars, sub-zero cooled, tempered

*T(Transverse) L(Longitudinal)

Typical stress rupture strength bar, sub-zero cooled, tempered

8 CORROSION RESISTANCE

S35500 has corrosion resistance superior to that of other quench-hardenable martensitic stainless steels. It offers good resistance to atmospheric corrosion and to a number of other mild chemical environments. Material in the double-aged or equalized and overtempered condition is susceptible to intergranular corrosion because of grain boundary precipitation of carbides. When this alloy is hardened by sub-zero cooling, it is not subject to intergranular attack.

The treatment for optimum stress-corrosion resistance is as follows:

Heat to 1875/1900°F (1024/1038°C), water quench, sub-zero cool 3 hours at -100°F (-73°C); reheat to 1700°F (927°C), air cool, sub-zero cool to -100°F (-73°C) for 3 hours, and then temper at 1000°F (538°C) for 3 hours.

For optimum corrosion resistance, surfaces must be free of scale, lubricants, foreign particles, and coatings applied for drawing and heading. After fabrication of parts, cleaning and/or passivation should be considered.

Important Note

The following 4-level rating scale is intended for comparative purposes only. Corrosion testing is recommended; factors which affect corrosion resistance include temperature, concentration, pH, impurities, aeration, velocity, crevices, deposits, metallurgical condition, stress, surface finish and dissimilar metal contact.

9 HEAT TREATMENT

Annealing

Heat to 1850/1900°F (1024/1038°C) and cool rapidly.

Hardening

The alloy can be hardened by either sub-zero cooling or by a double-aging treatment. Hardening by sub-zero cooling will result in higher strength than that attained by double aging. "Conditioning" of the alloy by rapid cooling from 1710/1750°F (932/954°C) is required before either hardening treatment.

Double aging

1350/1400°F (732/760°C) for 3-4 hours, rapid cool; 825/875°F (440/468°C) for 2-3 hours, air cool. The 1350/1400°F (732/760°C) treatment results in carbide precipitation so that the material will completely transfer to martensite when rapidly cooled to room temperature. The treatment at 825/875°F (440/468°C) after transformation provides further increases in strength and hardness.

10 WORKING INSTRUCTION

Hot working

The hot working characteristics of S35500 are similar to those of other chromium-nickel stainless steels. It is worked from a maximum temperature of 2100°F (1149°C) and finished in the range 1700/1800°F (927/982°C). The use of starting temperatures higher than 2100°F (1149°C) results in an increased amount of delta ferrite in the alloy. A relatively low finishing temperature prevents subsequent grain coarsening and promotes homogeneous precipitation of carbides. Cool forgings in air to room temperature. Then equalize and over-temper.

Cold working

In the annealed condition S35500 is handled in much the same manner as AISI Type 300 series stainless steels. It has, however, a high rate of work hardening, about the same as AISI Type 301. When desirable the rate of work hardening may be lowered slightly by heating the material to 600/700°F (316/371°C) before cold working.

In the hardened condition this alloy has sufficient ductility for limited forming and straightening operations.

Machinability

Successful machining of S35500 requires the same practices used for other stainless steels; i.e., rigid tool and work supports, slower speeds, positive cuts, absence of dwelling or glazing, and adequate amounts of coolant.

In the annealed condition this alloy has a high rate of work hardening and a tendency to be gummy. Machining this alloy in the annealed condition is not, therefore, recommended.

If machining is to be done after sub-zero hardening, tempering at 1000°F (538°C), hardness Rockwell C40, is suggested. This will provide improved machinability compared to that obtained after lower tempering treatments.

Optimum machinability of this alloy is obtained when the material is in the equalized and overtempered condition.

11 STANDARD SPECIFICATION

ASTM A484 / ASME SA484 General Requirements for Stainless Steel Bars, Billets and Forgings

ASTM A564 Hot rolled and cold finished age hardening stainless steel bar and shapes

ASTM A579 Superstrength Alloy Steel Forgings

ASTM A693 / ASME SA693 Precipitation Hardening Stainless and Heat-Resisting Steel Plate Sheet and Strip

ASTM A705 Age-Hardening Stainless Steel Forgings

AMS 5547

Steel, Corrosion and Heat-Resistant, Sheet and Strip, 15.5Cr - 4.5Ni - 2.9Mo - 0.10N, Solution Heat Treated (UNS S35500)

AMS 5549

Steel Corrosion and Heat Resistant Plate 15.5Cr - 4.5Ni - 2.9Mo - 0.1 ON Solution Heat Treated (UNS S35500)

AMS 5743

Steel, Corrosion and Heat Resistant, Bars and Forgings 15.5Cr - 4.5Ni - 2.9Mo - 0.10N Solution Heat Treated, Sub-Zero Cooled, Equalized, and Over-Tempered (UNS S35500)

AMS 5744

Steel, Corrosion and Heat-Resistant, Bars and Forgings, 15.5Cr - 4.5Ni - 2.9Mo - 0.10N, Heat Treated, 170 ksi (1172 MPa) Tensile Strength (UNS S35500)

AMS-S-8840A

Steel sheet and strip, corrosion-resistant, precipitation hardening (AM 350 and AM 355), premium quality

MIL-S-8840

Steel sheet and strip, corrosion-resistant, precipitation hardening AM 350 and AM 355 , premium quality

12 COMPETITIVE ADVANTAGE

(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Patented technologies.

(4) Ultra-purity smelting process: VIM + IG-ESR + VAR

(5) Excellent high performance.

13 BUSINESS TERM