Product Description
Stainless steels are known as high-alloy steels. They have excellent corrosion resistance in comparison with other steels as they contain more chromium.
Based on their crystalline structure, stainless steels are divided into three groups, namely, martensitic, austenitic and ferritic steels. A combination of martensitic and ferritic steels forms a fourth group known as precipitation-hardened steels.
The grade 446 stainless steel is a ferritic, non-heat treatable stainless steel that provides good resistance to high temperature oxidation and corrosion. The following datasheet provides more details of grade 446 stainless steel.
Description
| EN symbol (short) | X18CrN28 |
| Material No. | 1.4749 |
| UNS | S 44600 |
| AFNOR | Z 10 C 24 |
| Density kg/dm3 | 7,7 |
| Hardness HB 30 | 212 |
| Composition | No translation! |
| Category | Heat resistant steels and alloys |
| Structure | ferritic |
| Corrosion | No translation! |
| Additional characteristics | resistant to oxidising sulfuric gas forge scale temperature 2012 °F |
Availability
AISI – 446 IS AVAILABLE IN ALL THE BELOW SHAPES AND SIZES :
- ROUNDS : DIA 12 – 400 M.M
- SQUARE : 16 – 200 M.M
- HEX : 16 – 200 M.M
- PIPE : 16 OD – 400 OD X ANY ID
- FLAT : 16 X 12 – 300 X 200 M.M
Specifications
- ASTM A 276
- UNS S44600
- QQ S 763
- ASTM 446-1
- En 1.4749
- DIN X 18 CrN28
- SS 2322
| Chemical Composition Limits | |||||||
| Weight % | C | Si | Mn | P | S | Cr | N |
| Alloy 446 | 0.20 max | 0.5 | 0.8 | 0.030 max | 0.015 max | 26.5 | 0.2 |
Physical Properties
The following table shows the physical properties of grade 446 stainless steel.
| Properties | Metric | Imperial |
| Density | 7.80 g/cm3 | 0.282 lb/in³ |
Mechanical Properties
The mechanical properties of grade 446 stainless steel are displayed in the following table.
| Properties | Metric | Imperial |
| Tensile strength | 550 MPa | 79800 psi |
| Yield strength (@strain 0.200%) | 345 MPa | 50000 psi |
| Elastic modulus | 200 GPa | 29000 ksi |
| Poisson’s ratio | 0.27-0.30 | 0.27-0.30 |
| Elongation at break | 20% | 20% |
| Hardness, Brinell (estimated from Rockwell B) | 159 | 159 |
| Hardness, Knoop (estimated from Rockwell B) | 173 | 173 |
| Hardness, Rockwell A (estimated from Rockwell B) | 51.1 | 51.1 |
| Hardness, Rockwell B | 83 | 83 |
| Hardness, Vickers (estimated from Rockwell B) | 159 | 159 |
Thermal Properties
The thermal properties of grade 446 stainless steel are given in the following table.
| Properties | Metric | Imperial |
| Thermal expansion co-efficient (@0-100°C/32-212°F) | 10.4 µm/m°C | 5.78 µin/in°F |
| Thermal conductivity | 21.6 W/mK | 150 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to grade 446 stainless steel are:
- AISI 446
- ASTM A176
- ASTM A268
- ASTM A276
- ASTM A314
- ASTM A473
- ASTM A511
- ASTM A815
- DIN 1.4762
- QQ S763
- QQ S766
- ASME SA268
- ASTM A580
- FED QQ-S-763
- FED QQ-S-766
- MIL SPEC MIL-S-862
- SAE J405 (51446)
Fabrication and Heat Treatment
Machinability
Machinability of the grade 446 stainless steel is possible at slow speeds with positive feeds, rigid mounts and sharp tooling surfaces.
Welding
The grade 446 stainless steel can be easily welded using most of the traditional methods except oxyacetylene welding. Type 308 welding material can be used if required, but it will not exhibit scaling resistance equal to the base metal. Differences in coefficient of thermal expansion of base and weld metal has to be taken into consideration.
Forging
Forging can be started at 1149°C (2100°F) and completed at 871°C (1600°F). The last 10% of forging has to be performed below 871°C (1600°F) to gain grain refinement and room temperature embrittlement.
Hot Working
The hot working of grade 446 stainless steel is performed in between the ranges 1093- 1177°C (2000-2150° F). The last 10% of hot working has to be performed below 871°C (1600°F) to gain grain refinement
Temparature information
| Application area | ||
| Operation temperature | ºF to 2012 ºF | in air/scaling resistance |
| Solution heat treatment | ||
| Working temperature | 1472 ºF to 2102 ºF | air/Water |
| soft-annealed | |
| Working temperature | 1472 ºF to 1580 ºF |
| Explanation report | cooling in still air |
| annealing | ||
| Working temperature | 1382 ºF to 1652 ºF | afterwards: Ferrit |
Cold Working
The grade 446 stainless steel is more difficult to cold work than other stainless steels due to the high level of chromium content.
Annealing
Annealing of the grade 446 stainless steel has to be soaked at 816°C (1500°F) and then water quenched. The temperature should not exceed 900°C (1650°F) at any time and slow cooling below 649°C (1200°F) can cause loss of ductility.
Main fields of application
| Details of application | performs well under oxidising and sulfidising conditions |
| Certifications | |
| waste incineration plants | Müllverbrennunsanlagen |
| industral furnace engineering |
Applications
The grade 446 stainless steel can be used in the following products:
- X-ray tube bases
- Boiler baffles
- Oil burner components
- Annealing boxes
- Food processing industry
- Structural pipes
- Heat exchangers
- Plumbing
- Chemical industries
- Industrial mufflers
- Kiln linings
- Glass molds
- Furnace parts
- Water supply systems
- Power plant
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