8670m high carbon steel review: If you’re in the market for an affordable carbon steel knife, you may have come across options made with 8670m high carbon steel. While often overshadowed by more premium steels like VG-10 or 154CM, 8670M is gaining recognition among knife enthusiasts for its surprising edge retention, durability, and ease of sharpening.
But does this Chinese high-carbon steel live up to the hype when put to work? I decided to get my hands on a few 8670M steel knives to test out and discover “is 8670M steel good for knives” or not. Also to know if this steel really provides great value for money. After putting 8670m blades through weeks of slicing, dicing, and even prying – far beyond what any respectable cook would subject their knives to – I discovered the truth of its capabilities.
Read on for my full hands-on review to see how 8670m high carbon steel performs for kitchen knives and other EDC blades. I’ll compare it directly to better-known steels while revealing this steel’s strengths and limitations. By the end, you should know whether 8670m can produce a serviceable budget blade or if it is destined for the scrap pile.
Table of Contents
What is 8670M steel?
While steels like VG-10 and 154CM are household names among knife enthusiasts, you probably haven’t heard much about 8670M carbon steel. Despite being virtually unknown in the West, 8670M steel has become a popular choice among Chinese knife makers seeking budget-friendly steel with decent edge retention.
So what exactly is 8670M? It’s a Chinese high-carbon steel containing around 0.70% carbon, along with small amounts of silicon, manganese, and other alloying elements. While lacking the sophisticated metallurgy of premium Japanese and American steels, 8670M makes up for it with its low cost. The “M” likely stands for manganese, which strengthens the steel.
I was curious how this mysterious Chinese carbon steel would hold up. Does 8670M offer surprising value like beloved steels such as D2? Or will the low price translate to lackluster edge holding and cutting performance? I got my hands on some 8670M Chinese chef’s knives to see firsthand whether this budget steel is a diamond in the rough or just another lump of coal.
Related: How good is 420J2 steel for knives?
Other designations and standards
AISI 8670/8670M steel is alternatively available under these designations:
| Standard | Proprietor |
| DIN 72NiCrMo4-2 | Best BE86 |
| GB 20CrNiMo | Daido GM5 |
| JIS SKS5 | |
| UNS G86700 | |
| W-Nr 1.2703 Mod |
8670M steel Chemical composition
| Element | Portion | Effect |
| Chrome | 0.5% | Improves wear resistance, heat resistance and scale resistance. It increases tensile strength because it acts as a carbide former. Use of rust-proof or stainless steel, as it increases corrosion resistance from a mass proportion of 12.2%. Reduction in weldability. |
| Carbon | 0.75% | Increase hardness and tensile strength. In larger quantities, there is an increase in brittleness and a reduction in forgeability and weldability. |
| Copper | 0.0% | Improving weather resistance (surface oxidation). |
| Manganese | 0.6% | Improves hardness and tensile strength. |
| Molybdenum | 0.15% | Improves hardenability, tensile strength and weldability. Reduction in forgeability and ductility. |
| Nickel | 1.0% | Nickel increases tensile strength and yield strength. From 8% increase in corrosion resistance. |
| Phosphorus | 0.025% | Increases tensile strength, hardness and corrosion resistance but also brittleness. |
| Sulfur | 0.025% | Increases machinability but also brittleness. |
| Silicon | 0.35% | Improves strength. |
As we can see, 8670M is an alloy that offers hardness and (wear) strength, but with lower corrosion resistance.
What is the hardness (HRC) of 8670M steel?
8670M can be hardened to 61 HRC.
Does 8670M rust or is it a stainless steel?
8670M is susceptible to corrosion due to its low chromium content. To be considered stainless it would need a chromium content of at least 10.5 – 13% chromium dissolved in austenite or ferrite, depending on the definition (see here). However, it is by definition a stainless steel, since its sulfur and phosphorus content (so-called iron companion) does not exceed 0.025% (see here).
8670M steel Properties
According to the chemical composition and hardness of 8670M, this steel offers the following properties:
- Edge retention: with its carbon and manganese contents, the steel offers great hardness and good cut resistance.
- Corrosion resistance: With only 0.5% chromium, the corrosion resistance is not very good.
- Wear resistance: On the other hand, with 0.75% carbon, it offers good wear resistance.
- Sharpness: The rule is that the harder the steel, the harder it is to sharpen. 8670M is a hard steel, so it is not as easy to sharpen.
- Toughness: The toughness of 8670M is good thanks to the mixture of carbon, chromium, manganese as well as nickel.
Is 8670M a good knife steel?
The reader can certainly guess, because the answer is obvious – YES, 8670M is good for knives. You can use it well for knife making and even buy knives made of 8670M steel. However, I would like to remind you that due to its low corrosion resistance, it will not be ideal for all areas.
Because of just its low corrosion resistance, it should be avoided to use it in wet environments – for example, in the kitchen, fishing or hunting.
For those who only need hardness and toughness, 8670M steel is an excellent choice, offering good edge retention. But remember: always keep it clean and dry and a few drops of oil every now and then.
8670M steel equivalents
The steel that is probably closest to 8670M is probably A2 steel. Both steels offer good toughness, hardness, and edge retention to the same degree, and neither is very corrosion-resistant.
Conclusion: Is 8670M steel good for knives?
8670M is a rather lesser-known steel and is not widely used in the knife industry. It can be classified as a “classic steel” as it still follows the traditional rule of “if it’s hard, it will rust”, which many newer generation steels so not necessarily do.
Still, you can have a lot of fun with an 8670M steel, especially if you are a knifemaker, if only for the certain “exotic factor”.
More so, however, if you’re a ranger or a camper who needs a tough knife that can be pushed hard. However, 8670M knives are not exactly what one understands as cheap. If function is important but you have a tight budget, you should also take a look at the A2 Steel.
