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[China]
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Address: NO.288,YOUYI ROAD ,XI SHAN DISTRICT,WUXI CITY,CHINA
Contact name:Gao Ben
JIANGSU MITTEL STEEL INDUSTRIAL LIMITED |
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High Hardness 440A 440B 440C Stainless Steel Hexagonal Bar / Stainless Steel Hex Bar
Product Description:
| Product Name | stainless steel hexagon bar |
| Standard | JIS, AISI, ASTM, GB, DIN |
| Size | Diameter : S6-S65mm or as request |
| Length | Normal long 4M, Or as your request |
| Surface | Bright ,hairline finsh |
| Technics | cold drawn and polishing |
| Mainly Grade | 201 303 304 304L 316L 410 420 431 440(A B C) 17-4PH.etc |
| Application | construction field, ships building industry, petroleum & chemical industries, war and electricity industries, food processing and medical industry, boiler heat exchanger, machinery and hardware fields ,etc. |
| Packing | Export standard or as customers' requirement |
| Delivery time | Within 15 working days, according to customers' quantities |
| Payment | L/C or T/T |
| MQQ | 1 Ton |
| Quality | High Quality.SGS inspection is accepted if needed |
| Productivity | 500 Tons/Month |
| Attention | We will supply you good quality and bottom price and first-class service in china and hope to be your golden supplier |
Size of our hexagon stainless steel bar in stock:
| 201 304 316L stainless steel hexagon bar | |
| Size | S6 S8 S10 S11 S12 S13 S14 S15 16 S17 S18 S19 S20 S21 S22 S24 S25 S26 S28 S29 S30 S31 S32 S33 S36 S38 S40 S41 S42 S46 S50 S55 S60 S65 |
Grade 440C stainless steels are high carbon steels, which attain the highest hardness, wear resistance and strength of all stainless steel grades after heat treatment. These properties make this grade suitable for applications such as valve components and ball bearings. Grade 440A and 440B stainless steels, on the other hand, have similar properties - except for a slightly lower percentage of carbon in grade 440A.
All three forms of grade 440 steels are commonly used. However, grade 440C is more readily available than the other standard grades. Grade 440F, a free-machining type of grade 440 series, is also available with a high carbon content similar to that of grade 440C. Martensitic steel grades are high-hardness steels, usually fabricated using techniques that require hardening and tempering treatments.
These grades have a corrosion resistance lower than that of other austenitic grades. The applications of martensitic steels are limited by the loss of strength caused by over-tempering at high temperatures, and loss of ductility at temperatures below zero.
The following section discusses the properties of grade 440 bar products covered under ASTM A276. These values may not be similar to that of other forms such as forgings and plates.
The chemical compositions of various elements of grade 440 stainless steels are tabulated below:
Table 1. Chemical composition ranges of grade 440 stainless steels
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 440A | min. max. | 0.6 0.75 | - 1 | - 1 | - 0.04 | - 0.03 | 16 18 | - 0.75 | - | - |
| 440B | min. max. | 0.75 0.95 | - 1 | - 1 | - 0.04 | - 0.03 | 16 18 | - 0.75 | - | - |
| 440C | min. max. | 0.95 1.20 | - 1 | - 1 | - 0.04 | - 0.03 | 16 18 | - 0.75 | - | - |
Table 2. Mechanical properties of grade 440C stainless steels
| Tempering Temperature (°C) | Tensile Strength (MPa) | Yield Strength 0.2% Proof (MPa) | Elongation (% in 50mm) | Hardness Rockwell (HR C) | Impact Charpy V (J) |
| Annealed* | 758 | 448 | 14 | 269HB max# | - |
| 204 | 2030 | 1900 | 4 | 59 | 9 |
| 260 | 1960 | 1830 | 4 | 57 | 9 |
| 316 | 1860 | 1740 | 4 | 56 | 9 |
| 371 | 1790 | 1660 | 4 | 56 | 9 |
* Annealed properties are typical for Condition A of ASTM A276# Brinell hardness is ASTM A276 specified maximum for annealed 440A, B and C.
The following table outlines the physical properties of grade 440 stainless steels:
Table 3. Typical physical properties of grade 440 stainless steels
| Grade | Density (kg/m3) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (μm/m/°C) | Thermal Conductivity (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Electrical Resistivity (nΩ.m) | |||
| 0-100°C | 0-200°C | 0-600°C | at 100°C | at 500°C | |||||
| 440A/B/C | 7650 | 200 | 10.1 | 10.3 | 11.7 | 24.2 | - | 460 | 600 |
Grade specifications for 440 stainless steels are given in the following table:
Table 4. Grade specifications of grade 440 stainless steels
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| 440A | S44002 | - | - | SUS 440A | |||
| 440B | S44003 | 1.4112 | X90CrMoV18 | SUS 440B | |||
| 440C | S44004 | - | - | 1.4125 | X105CrMo17 | - | SUS 440C |
Suitable alternatives to grade 440 stainless steels are listed in the table below:
Table 5. Possible alternative grades to 440 stainless steels
| Grade | Reasons for choosing 440C |
| 440A/B | Slightly softer and more corrosion resistant grade needed |
| 440F | High machinability required, with same hardness and hardenability as 440C |
| 420 | Lower strength and hardness needed than any of the 440 grades |
| 416 | Higher machinability required, and the much lower hardness and strength is still adequate |
Grade 440 stainless steels exhibit excellent resistance to mild acids, alkalis, foods, fresh water and air. A smooth polished surface also helps grade 440 steels resist corrosion in tempered, passivated and hardened conditions.
Grade 440C steels exhibit corrosion resistance similar to that of grade 304 steels.
Grade 440 stainless steels should not be used at temperatures below the relevant tempering temperature, due to loss of mechanical properties caused by over-tempering.
Annealing — Grade 440 stainless steels are full annealed at 850 to 900°C, followed by slow furnace-cooling at about 600°C and air-cooling. Sub-critical annealing is carried out at 735 to 785°C, followed by slow furnace-cooling.
Hardening — Grade 440 stainless steels are heated at 1010 to 1065°C, then quenched in air or oil. Oil quenching is usually carried out for heavy sections. Following this process, these steels are tempered at temperatures from 150 to 370°C, to achieve a high hardness and improved mechanical properties.
Tempering at temperatures between 425 and 565°C should be avoided as the corrosion and impact resistance properties of grade 440 tend to reduce in this range. Also, tempering of these grades at 590 to 675°C will result in high impact resistance and loss of hardness.
During welding, grade 440 stainless steels are pre-heated at 250°C, followed by full annealing. Grade 420 filler rods can be used to achieve a high hardness weld. Grade 309 or 310 filler rods will, however, provide soft welds, having high ductility.
Grade 440 stainless steels can be easily machined in their annealed state. Machining these grades after hardening is extremely difficult, or impossible in some cases.
Grade 440 stainless steels find applications in the following:
Service:
Cutting our bars into any length. Cutting side is smooth without burr.
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