If you are sourcing 420 or 420F stainless steel round bars, rods, or machined components, understanding the differences between these two grades is essential for choosing the right material and controlling your machining cost. With over 18 years of stainless steel supply experience, GNEE offers full-size 420 and 420F stainless steel stock with MTC 3.1 certification, fast delivery, and competitive pricing.
This article explains the key differences, provides chemical & mechanical data, market pricing, and answers frequently searched buyer questions to help you make a confident purchasing decision.
What are 420 and 420F stainless steel?
420 stainless steel is a martensitic stainless steel characterized by high hardness after heat treatment, good wear resistance, and moderate corrosion resistance. 420F stainless steel is a free-machining version of 420, with added sulfur (S) to improve its machinability, making it easier to process and suitable for mass production of CNC parts.
What is the composition of SS 420F?
420F stainless is characterised by having a 0.28-0.38 carbon, and 15-17% chromium content. This mix of analysis gives 420F stainless steel an outstanding corrosion resistance and exceptional wear properties after heat treatment. Superior to 410 and 416 type stainlesses for most applications.
Chemical Composition (wt%)
| Element | 420 | 420F |
|---|---|---|
| Carbon (C) | 0.15–0.36 | 0.15–0.36 |
| Chromium (Cr) | 12–14 | 12–14 |
| Sulfur (S) | ≤0.03 | 0.15–0.35 (added) |
| Manganese (Mn) | ≤1.0 | ≤1.0 |
| Silicon (Si) | ≤1.0 | ≤1.0 |
Mechanical Properties
| Property | 420 | 420F |
|---|---|---|
| Tensile Strength | 700–850 MPa | 650–750 MPa |
| Yield Strength | 450 MPa | 415 MPa |
| Hardness (Annealed) | 180–220 HB | 170–200 HB |
| Hardness (Hardened) | Up to HRC 50–55 | Up to HRC 48–52 |
| Machinability | Standard | Excellent (Improved) |
420 vs. 420F Stainless Steel: Machining
420F stainless steel has superior machinability compared to 420 stainless steel because it incorporates sulfur in its composition, improving machinability. While 420 stainless steel is hard and easy to machine, its high carbon content can lead to relatively poor machinability during machining. 420F stainless steel, on the other hand, is designed for improved cutting efficiency.
420 vs. 420F Stainless Steel: Corrosion Resistance
The main difference between 420 and 420F stainless steel lies in their ease of machining and corrosion resistance. 420F has a higher sulfur content, making it easier to cut, but also reducing its corrosion resistance, making it more susceptible to corrosion and pitting. 420, however, offers better corrosion resistance and is suitable for applications requiring high corrosion resistance, but its machinability is relatively poor.
420 vs. 420F Stainless Steel: Heat Treatment
420 can be hardened to HRC 50+ and is widely used in cutting tools, equipment, and wear-resistant parts. 420F can also be hardened, but its hardness is not as good as the standard 420.
What is the difference between SS 316 and SS 420?
The key difference lies in their primary advantages: 316 excels in harsh, corrosive environments, whereas 420 is designed for applications needing superior strength and hardness after heat treatment.
420 Stainless Steel is available in various forms, such as sheets, profiles, bars, pipes, fittings, coils, and rods. These forms allow for a wide range of fabrication processes, including machining, forging, and stamping, which are used to create finished products like knives, surgical instruments, and industrial tools. It can also be cold-rolled or hot-rolled, depending on the desired surface finish and mechanical properties.
