Custom 450 / XM-25 Corrosion Resistant Metals S45000 With Moderate Strength

UNS S45000 (Custom 450, XM-25) semi-products for industrial parts requesting high strength in corrosive environments

1 PRODUCT

UNS S45000 (Custom 450, XM-25) semi-products for food industrial parts requesting high strength in corrosive environments.

UNS S45000 is available in product forms as plate, sheet, strip, pipe, tube, bar (round, flat, hexagon, square, shapes), wire (profile, round, flat, square), forgings, fastener (bolts, nuts, studs, washers) etc.

2 EQUIVALENT DESIGNATION

Custom 450, Alloy 450, Grade 450, XM-25, CarTech® Custom 450®

3 APPLICATION

S45000 stainless steel alloy is mainly used in applications where martensitics fail in terms of corrosion resistance, and standard austenitics fail in terms of strength requirements in corrosive environments.

It is mainly used for following applications

Screens for the pulp and paper industry

Medical devices

Aircraft parts

Power generation applications

Chemical processing

Nuclear applications

4 OVERVIEW

S45000 is a martensitic age-hardenable stainless steel which exhibits very good corrosion resistance (similar to that of 304 stainless) with moderate strength (similar to that of Stainless Type 410). The alloy has a yield strength somewhat greater than 100 ksi (689 MPa) in the annealed condition, but is easily fabricated. A single-step aging treatment develops higher strength with good ductility and toughness.

This stainless can be machined, hot-worked, and cold-formed in the same manner as other martensitic age-hardenable stainless steels. A particular advantage is ease of welding and brazing.

S45000 stainless is generally supplied in the annealed condition, requiring no heat treatment by the user for many applications. Because it has corrosion resistance like 304 stainless but three times the yield strength, it has been used in applications where 304 stainless was not strong enough. On the other hand, it has also replaced Type 410 stainless directly on a strength basis where type 410 stainless had insufficient corrosion resistance. Mechanical properties will depend on the aging temperature selected.

5 CHEMICAL COMPOSITION (wt%):

6 PHYSICAL PROPERTY

Melting range: 2500-2550°F

Density:

Annealed: 7750 kg/m³(0.280 lb/in³)

Condition H 900: 7760 kg/m³(0.280 lb/in³)

Mean specific heat: 73 to 216°F, condition H900, 0.1140 Btu/lb/°F

Poisson's ratio condition H 900: 0.290

Mean coefficient of thermal expansion

Thermal conductivity

Modulus of elasticity (E)

Modulus of rigidity (G)

Electrical resistivity

7 MECHANICAL PROPERTIES

Typical room temperature mechanical properties - bar

Typical room temperature mechanical properties - strip

8 CORROSION RESISTANCE

S45000 stainless has resisted atmospheric corrosion including salt water atmospheres. It shows excellent resistance to rusting and pitting in 5% and 20% salt spray at 95ºF (35ºC). Tests in hot concentrated nitric acid show corrosion resistance approaching that of Type 304.

Optimum corrosion resistance for this alloy is obtained in the annealed condition. However, age hardening results in only a slight change.

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.

Sour service

S45000 stainless has acceptable resistance to sulfide stress cracking at Rockwell C 31 maximum hardness per NACE MR-01-75, "Sulfide Stress Cracking Resistant Metallic Materials for Oil field Equipment." Refer to the current document for details on acceptable conditions. A comparison is made for alloys heat treated in accordance with MR-01-75 requirements. Threshold stresses are intended for comparative purposes only and should not be used as design stress level.

9 HEAT TREATMENT

Condition A (Solution treated or annealed)

Heat to 1875/1925ºF (1024/1052ºC), hold one hour at heat and cool rapidly. Water quenching or oil quenching is preferred for optimum response to aging, but air quenching is suitable for thin sections.

S45000 stainless will normally be supplied from the mill in Condition A, ready for service or for subsequent age-hardening.

Age hardening

Condition H900, H950, H1000, H1050, H1150 (Precipitation or Age hardenend)

Tensile strength and yield strength are increased by aging at 900/1050ºF (482/566ºC) for 4 hours, followed by air cooling. The 900ºF (482ºC) age produces the optimum combination of strength, ductility, and toughness. Overaging at temperatures up to 1150ºF (621ºC) increases the ductility and decreases strength.

10 WORKING INSTRUCTION

Hot working

This alloy is easily hot worked in the temperature range of 1650/2300ºF (900/1260ºC). The optimum hot-working range is 2100/2150ºF (1150/1177ºC) for the best combination of ease of working and fine grain size. Cool forgings in air to room temperature and anneal.

Cold working

The work-hardening rate of S45000 is relative low, permitting a good deal of cold reduction without intermediate annealing. Deep-drawing or stretching operations with sharp bends which produce localized elongation are to be avoided.

Machinability

S45000 stainless has been machined successfully using the same practices employed with other martensitic stainless steels at comparable hardness levels. It is preferred to use positive feeds and slow speeds to achieve good results.

Additional machinability notes

When using carbide tools, surface speed feet/minute (sfpm) can be increased between 2 and 3 times over the high speed suggestions. Feeds can be increased between 50 and 100%.

Figures used for all metal removal operations covered are average. On certain work, the nature of the part may require adjustment of speeds and feeds. Each job has to be developed for best production results with optimum tool life. Speeds or feeds should be increased or decreased in small steps..

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

ASTM A705 Age hardening stainless steel forgings

ASTM A959 Specifying harmonized standard grade compositions for wrought stainless steels

MR0175

AMS 5763

Steel, Corrosion Resistant Bars, Forgings, Tubing, and Rings, 15Cr - 6.5Ni - 0.75Mo - 0.50Cb (Nb) - 1.5Cu, Solution Heat Treated

AMS 5773

Steel, Corrosion-Resistant, Bars, Wire, Forgings, Tubing, and Rings, 15Cr - 6.5Ni - 0.75Mo - 0.30 Cb (Nb) - 1.5Cu,Consumable Electrode Remelted, Solution Heat Treated, Precipitation Hardenable

AMS 5859

Steel, Corrosion Resistant, Sheet, Strip, and Plate, 15Cr - 6.5Ni - 0.75Mo - 0.30 (Cb+Ta) - 1.5Cu Consumable Electrode Melted, Solution Heat Treated Precipitation Hardenable

AMS 5863

Steel, Corrosion Resistant, Sheet, Strip, and Plate 15Cr - 6.5Ni - 0.75Mo - 0.60Cb - 1.5Cu Solution Heat Treated, Precipitation Hardenable (UNS S45000)

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