420B STAINLESS STEEL
There are many types of stainless steel available. Stainless steel is identified in accordance with microstructure. Different chemical composition relates to mechanical properties and other distinction.
Different steel grade exhibits distinct mechanical properties. It is important to understand the small unique dissimilarity between the uncountable stainless steel grades. Choosing the best grade will conduct the right application in the engineering sector./p>
About Grade 420B Stainless Steel
Stainless steel has one significant application in biomedical applications. It is known as surgical steel. Strength and corrosion resistance ability is designated characteristic for surgical steels. Surgical steel is commonly used in orthopedic and dental implants. It is also used in surgical instruments like forceps, retractors, etc
Martensitic stainless steel shows strength, durability, and moderate corrosion resistance. It shows considerable ductility and machinability.
420B is a martensitic grade and is used in surgical steels.
Grade 420B Stainless Steel
Grade 420B is a high carbon version of grade 420 stainless steel. It is high carbon content which optimizes hardness. Like grade 420, grade 420B stainless steel can be hardened by heat-treatment. Grade 420B is martensitic stainless steel for instruments. It offers optimal hardness and good resistance.
Weldability is poor for AISI 420B . Fabrications of martensitic stainless steel required hardening and tempering operations. Grade 420B is not used for high temperatures, as it attains softness and loss of corrosion resistance.
Good corrosion resistance and hardness are the attributes that make it ideal for its application. AISI 420B is widely used in surgical and dental instruments, scissors, pump and valve parts, etc.
Composition
Grade 420B is high carbon with low chromium stainless steel. It contains 0.26 -0.35 % carbon and 12-14% chromium with traces of silicon, manganese, sulfur, and phosphorous.
| Element | Content (%) |
| Carbon (C) | 0.26 - 0.35 |
| Chromium (Cr) | 12.00 - 14.00 |
| Manganese (Mn) | Trace |
| Silicon (Si) | Trace |
| Sulfur (S) | Trace |
| Phosphorous (P) | Trace |
Physical Properties
| Property | Value |
| Density | 7.73 g/cm³ |
| Modulus of Elasticity | 195 GPa |
| Electrical Resistivity | 68 Microhm-cm |
Thermal Properties
| Property | Value |
| Thermal Expansion Coefficient | 10.2 µm/m°C (1-100°C) |
| Thermal Conductivity | 27.4 W/mK (room temperature) |
Mechanical Properties
| Property | Value (Annealed) |
| Tensile Strength | 800 MPa |
| Yield Strength | 650MPa |
| Hardness | 245 HB |
| Elongation | 10% |
Megnetic Properties
Grade 420B shows magnetic permeability in annealed and heat-treated conditions.
Heat Treatment
Grade 420 can be annealed by heating its temperature from 840-900 °C. Then slow furnace cooling takes plate till 600°C, followed by air cool.
Hardening: Material is heated in a temperature range of 980-1035 °C, followed by oil quenching.Oil quenching is suggested for heavy segments.
Tempering: Tempering is done in the temperature range of 150-370°C. Tempering at this temperature enables high hardness and improved mechanical properties.
Properties
Corrosion Resistance: Grade 420B attains maximum corrosion resistance under hardened conditions. It offers good corrosion resistance in mild environments. Grade 420B offers corrosion resistance to fresh water, alkalis, air, food, and mild acid. It provides corrosion resistance ammonia, blood, sterilizing solutions, carbonic acids, crude oil, detergents, dilutes nitric acids, steam, and vinegar.
A polished and smooth surface finish tends to give excellent results. The corrosion resistance property of grade 420 falls under annealed conditions. It is not suggested to be used in the annealed condition.
Austenitic grades offer more corrosion resistance than grade 420.
Welding: Grade 420B emits limited weldability, as it has a hardened structure
Applications: Good corrosion resistance and hardness are the characteristics that make it ultimate for its application. Grade 420B is commonly used in dental and surgical instruments. Other common applications for grade 420 are as follows:
- Surgical equipment
- Needle valves
- Knife blades
- Hand tools
- Fasteners
Ambica steels offer superior fine quality grades 420B bars. A grade 420B is a special grade produced by Ambica steels. Bars are available in round, square, flat, hexagonal, and customized shapes. Inquiry and orders are welcome.
420B Stainless Steel Bars from Ambica Steels
Ambica Steels manufactures and exports superior fine-quality 420B stainless steel bars. As an ISO-certified manufacturer, Ambica Steels produces 420B as a specialty grade, available in round, square, flat, hexagonal, and customized shapes for bulk and export orders to 75+ countries. Contact Ambica Steels for inquiries, technical datasheets, and pricing.
Request a Quote for 420B Stainless Steel Bars
Frequently Asked Questions
Q1. What is 420B stainless steel?
420B stainless steel is a high-carbon martensitic grade with 12-14% chromium content. Heat treatment hardens it, and it delivers moderate corrosion resistance along with high hardness, which makes it suitable for surgical instruments, dental tools, and cutting applications.
Q2. What is the difference between 420 and 420B stainless steel?
420B contains a higher carbon percentage (0.26-0.35%) than standard grade 420 (typically up to 0.15%). The additional carbon in 420B raises the achievable hardness after heat treatment, while both grades share a similar chromium range and martensitic structure.
Q3. Is 420B stainless steel magnetic?
Yes. 420B stainless steel shows magnetic permeability in both annealed and heat-treated conditions, unlike austenitic grades such as 304 or 316.
Q4. Can you weld 420B stainless steel?
420B offers poor weldability because of its hardened martensitic structure and high carbon content. Fabricators typically preheat the material, weld with matching filler metal, and apply post-weld tempering to reduce the risk of cracking.
Q5. What are the common applications of 420B stainless steel?
Manufacturers use 420B stainless steel for surgical and dental instruments, scissors, knife blades, needle valves, hand tools, fasteners, and pump and valve parts, where high hardness and wear resistance matter most.
Q6. What shapes does Ambica Steels supply 420B bars in?
Ambica Steels supplies 420B stainless steel bars in round, square, flat, and hexagonal shapes, and produces customized shapes on request for bulk and export orders.