Martensitic Stainless Steel Seamless Welded Pipe AISI 440A/B/C 40mm
Overview
Stainless 440C is a high-carbon martensitic stainless steel. As a martensitic stainless steel, 440C is magnetic and can be hardened by heat treatment. The high carbon content in 440C provides high hardness and strength. Despite this carbon content, the chromium content is sufficient to retain its stainless characteristics. Martensitic steels are commonly used in applications where high strength and moderate corrosion resistance is required.
Application
Valve Seats
Surgical Instruments
Bearings
Bushings
Nozzles
Structural Aircraft Parts
440 Stainless Pipe Chemical Composition
| 440 Stainless Steel Chemical Composition, % | |||||||||
| ASTM | Steel | AISI (UNS) | C | Si (≤) | Mn (≤) | P (≤) | S (≤) | Cr | Mo (≤) |
| ASTM A276/A276M | 440 Steel | 440A (S44002) | 0.60-0.75 | 1 | 1 | 0.04 | 0.03 | 16.0-18.0 | 0.75 |
| 440B (S44003) | 0.75-0.95 | 1 | 1 | 0.04 | 0.03 | 16.0-18.0 | 0.75 | ||
| 440C (S44004) | 0.95-1.20 | 1 | 1 | 0.04 | 0.03 | 16.0-18.0 | 0.75 | ||
Physical Properties
| SS440 Physical Properties | |
| Density (g/cm3) | 7.8 |
| Melting point (℃) | 1370-1480 |
| Specific heat capacity, J/(Kg·K) | 460 (0-100 ℃) |
| Electrical resistivity (μΩ·m) | 0.6 (20 ℃) |
| Elastic modulus (GPa) | 200 |
| Thermal conductivity (W/m·K) | 24.2 (100 ℃) |
| Coefficient of thermal expansion | 10.2 (0-100 ℃) |
Mechanical Properties Stainless Steel 440
| Mechanical Properties | |||||
| Grade (UNS) | Tensile Strength (MPa) ≥ | Yield Strength, 0.2%, ≥ (MPa) | Elongation in 50 mm (%) ≥ | Reduction in area (%) | Hardness |
| 440A (S44002) | 725 | 415 | 20 | 95 HRB | |
| 1790 | 1650 | 5 | 20 | 51 HRC | |
| ≤ 965 | |||||
| 440B (S44003) | 740 | 425 | 18 | 96 HRB | |
| 1930 | 1860 | 3 | 15 | 55 HRC | |
| ≤ 965 | |||||
| 440C (S44004) | 760 | 450 | 14 | 97 HRB | |
| 1970 | 1900 | 2 | 10 | 57 HRC | |
| ≤ 965 | |||||
SS440 Heat Resistance
AISI 440 has good oxidation resistance in intermittent use below 815 °C and continuous use up to 760 °C in air.
Heat Treatment of SS440
SS440 heat treatment including annealing, quenching, tempering and stress relieving, etc.
Annealing
Subcritical annealing temperature range: 675-760 ℃ (1250-1400 ℉)
Full annealing: insulation from 845-900 °C (1550-1650 ℉) to completely soaking, then furnace cooling to 790 °C, continue cooling to 595 ° C at a cooling rate of 15-25 °C/h, then air cool to room temperature.
Isothermal Annealing: heat treat to 845-900 °C, kept at 690 °C for 4 hours.
SS440 Quenching
Heat to 1010-1065 °C and quench in air or oil. To ensure maximum dimensional stability, cold treatment should be performed immediately after cooling to room temperature
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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