AISI 420F UNS S42020 Martensitic Stainless Steel Bars and plates
It is a free-cutting martensitic stainless steel, an improved grade of high-carbon martensitic stainless steel. It offers moderate corrosion resistance and is not suitable for use in highly corrosive media such as seawater and dilute sulfuric acid. It should also be avoided in welded structures. If welding is necessary, TIG welding (argon arc welding) with controlled heat input is recommended, requiring preheating to 200°C before welding and tempering at 650°C after welding.
Applications of UNS S42020
In the automatic machining industry, it is suitable for precision parts and automotive components, such as screws for electronic equipment and brake system pistons. Its machining efficiency is over 30% higher than that of 3Cr13. In the field of tools and cutlery, it is suitable for general tools and mold parts, such as woodworking saw blades, ejector pins for injection molds, and guide pins for stamping dies, which require wear resistance and easy machinability.
Equivalent Grades and Commonly Used Specifications of UNS S42020
|
Steel Grade |
Specification |
Specification Name |
| Y3Cr13 / Y30Cr13 / S42037 | GB/T 1220 | Stainless steel bars |
| GB/T 4356 | Stainless steel wire rods | |
| GB/T 20878 | Stainless steels — Designation and chemical composition | |
| UNS S42020 / 420F | ASTM A582/A582M | Standard Specification for Free-Machining Stainless Steel Bars |
| 1.4029 / X29CrS13 | EN 10088-3 | Stainless Steels Part 3-Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes |
| SUS420F | JIS G 4303 | Stainless Steel bars |
| JIS G 4308 | Stainless steel wire rods | |
| JIS G 4318 | Cold finished stainless steel bars | |
| Products produced as per other specifications or technical agreements (if need) are available. | ||
Typical Chemical Composition of UNS S42020
|
Elements |
C | Si | Mn | P | S | Ni | Cr |
Mo |
| Contents% | 0.26~0.35 | ≤1.00 | ≤1.25 | ≤0.060 | ≥0.15 | ≤0.60 | 12.00~14.00 |
≤0.60 |
| Products produced as per other specifications or technical agreements (if need) are available. | ||||||||
Typical Heat Treatment Condition and Mechanical Properties of UNS S42020
|
Delivery Condition |
Mechanical Properties of Heat-Treated Specimens | ||||||
| Rp0.2/(N/mm2) | Rm/(N/mm2) | A/% | Zb/% | Aku2d/J | HBW |
HRC |
|
|
Annealed Condition（800℃-900℃, cool slowly） |
/ | / | / | / | / | ≤235 | / |
| Q+T（920℃-980℃, oil; 600℃-750℃, cool rapidly） | ≥540 | ≥735 | ≥8 | ≥35 | ≥24 | ≥217 |
/ |
| Products produced as per other specifications or technical agreements (if need) are available. | |||||||
Product Forms and Size Range of UNS S42020
|
Product forms |
Size range |
|
Bars |
Diameter or side length: 5.0mm~1000mm |
| Flats |
thickness: 4.0mm~1000mm width: 300mm~2200mm |
| Produce as other form and size according to technical requirements are available. | |
