Original material
TNK has developed two proprietary materials: 15MH — a non-magnetic stainless steel that offers high hardness, excellent wear resistance, and outstanding corrosion resistance. KWS440MA — a martensitic alloy that delivers similar performance to SUS4C, with enhanced sliding properties and reduced cost. Its wear resistance can be further improved through heat treatment.
15MH / KWS4MA
It has the same corrosion resistance as SUS304 and a surface hardness of Hv500. It is normally very difficult to achieve both high hardness and high hardness when using austenitic stainless steel, but TNK makes it possible.
Our original materials are ideal for applications requiring non-magnetic properties, including solenoids and precision devices.
15MH + SVC Processing
By applying TNK’s proprietary “SVC treatment” to 15MH, TNK achieve a surface hardness of HV800 or higher.
In addition to its non-magnetic nature and high hardness, the material features a thicker hardened layer than conventional quenching or carburizing methods, resulting in a more gradual decrease in surface hardness with depth. It has been adopted in a variety of industries, including automotive parts and industrial machinery. This is a highly durable, long-lasting material. TNK encourages you to consider it.
>>Click here for information on "SVC processing"
| Nonmagnetic | Permeability: 1.01μ or less It is used to prevent magnetic interference with magnetic media and to stop metals from sticking together due to magnetism. |
| High hardness | Surface hardness HV500 (approximately 2.5 times that of SUS304) It is used in components that require wear resistance, such as rotating shafts and sliding shafts. *HV700 is also possible with special processing. |
| Corrosion resistance | Equivalent to SUS304 It is used in environments where rust is undesirable, such as outdoors, near the coast, and around water. |
Ingredients and mechanical/physical properties
The table below outlines the chemical composition and mechanical/physical properties of 15MH.
You can get a better understanding of its characteristics by comparing it with SUS420J2, a typical martensitic stainless steel, and SUS304 and SUS316, austenitic stainless steels.
Ingredients
| Material | C | Si | Mn | P | S | Ni | Cr | Mo | N |
| 15MH | 0.05 ~ 0.25 | 1.00 or less | 9.00 ~ 16.00 | 0.060 or less | 0.030 or less | 1.00 ~ 6.00 | 16.00 ~ 19.00 | - | 0.20 ~ 0.40 |
| SUS304 | 0.08 or less | 1.00 or less | 2.00 or less | 0.045 or less | 0.030 or less | 8.00 ~ 10.50 | 18.00 ~ 20.00 | - | - |
| SUS316 | 0.08 or less | 1.00 or less | 2.00 or less | 0.045 or less | 0.030 or less | 10.00 ~ 14.00 | 16.00 ~ 18.00 | 2.00 ~ 3.00 | - |
| SUS420J2 | 0.26 ~ 0.40 | 1.00 or less | 1.00 or less | 0.040 or less | 0.030 or less | 0.60 or less | 12.00 ~ 14.00 | - | - |
Mechanical and physical properties (room temperature)
| Material | 硬度 HV |
density g / cm3 |
Modulus of Elasticity × 104N/mm2 |
specific heat J/(g・k) |
Thermal conductivity W/(m・k) |
Coefficient of thermal expansion × 10-6/ ℃ |
specific electrical resistivity μΩ cm |
magnetic |
| 15MH | 500 | 7.75 | 19.50 | 0.46 | 14.7 | 13.1 | 70 | Nonmagnetic |
| SUS304 | 200 or less | 7.93 | 19.30 | 0.59 | 16.3 | 16.1 | 72 | Weak magnetism |
| SUS316 | 200 or less | 8.03 | 19.30 | 0.50 | 15.2 | 17.3 | 74 | Weak magnetism |
| SUS420J2 | 500 ~ 700 | 7.75 | 20.60 | 0.46 | 25.0 | 10.4 | 56 | Strong magnetism |
KWS4MA Features
KWS440MA is a proprietary material developed by TNK as an alternative to SUS440C. It offers the same surface hardness (HV700) and corrosion resistance as SUS440C, but with superior sliding properties and approximately two-thirds the cost. It is used in automotive components, medical devices, and household appliances.
| Wear resistance | Hardness exceeds HV700 and is equivalent to SUS440C |
| Corrosion resistance | Equivalent to SUS440C |
| Sliding property | Sliding properties exceeding those of SUS440C |
| Price | Approximately 440/2 the price of SUS3C |
Ingredients and mechanical/physical properties
The table below shows the composition and mechanical/physical properties of KWS4MA.
You can get a better understanding of its characteristics by comparing it with typical martensitic stainless steels such as SUS420J2 and SUS440C.
Ingredients
| Material | C | Si | Mn | P | S | Ni | Cr | Mo | N |
| KWS4MA | 0.45 to 0.55 | 0.80 or less | 0.80 or less | 0.040 or less | 0.030 or less | 0.60 or less | 12.5 to 14.00 | - | - |
| SUS440C | 0.95 to 1.20 | 1.00 or less | 1.00 or less | 0.040 or less | 0.030 or less | 0.60 or less | 16.00 to 18.00 | 0.75 or less | - |
| SUS420J2 | 0.26 to 0.40 | 1.00 or less | 1.00 or less | 0.040 or less | 0.030 or less | 0.60 or less | 12.00 to 14.00 | - | - |
Mechanical and physical properties (room temperature)
| Material | 硬度 HV |
density g / cm3 |
Modulus of Elasticity × 104N/mm2 |
specific heat J/(g・k) |
Thermal conductivity W/(m・k) |
Coefficient of thermal expansion × 10-6/ ℃ |
specific electrical resistivity μΩ cm |
magnetic |
| KWS4MA | 600 to 800 | 7.75 | 20.60 | 0.46 | 24.7 | 10.6 | 67 | Strong magnetism |
| SUS440C | 600 to 800 | 7.78 | 22.05 | 0.46 | 24.2 | 10.6 | 60 | Strong magnetism |
| SUS420J2 | 500 to 700 | 7.75 | 20.60 | 0.46 | 25.0 | 10.4 | 56 | Strong magnetism |
For inquiries about this product, please click here
Other materials
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MATERIAL
Corrosion resistance
Corrosion resistance
In metals, corrosion resistance refers to resistance to rust. As rust progresses, the metal will no longer be able to maintain its strength and will no longer be able to perform its intended function. In order to prevent rust, it is important to create an environment that is less susceptible to rust, as well as to select materials that are resistant to rust.
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MATERIAL
Heat resistance
Heat-resistant
Heat-resistant materials include stainless steel, heat-resistant steel, ceramics, etc. Ceramics have high heat resistance and abrasion resistance, but are expensive and have poor impact resistance. Please select the appropriate material depending on the application.
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MATERIAL
Non magnetic
Nonmagnetic
Austenitic stainless steel is non-magnetic, but it can become magnetic due to work hardening. It is very difficult to achieve both non-magnetic and wear resistance at the same time. There are many types of stainless steel, so please choose the appropriate material.