How is stainless steel utilised in the automotive and transport industries?

Stainless steel is important in the automotive and transport industries due to its high strength, corrosion resistance, and durability. Here’s an overview of how stainless steel, particularly from companies like Jindal Stainless, is shaping automotive and transport developments:

Key developments and applications

Automotive industry

• Exhaust systems:

Stainless steel is a primary material in car exhaust systems, particularly around the catalytic converter area, because it can withstand high temperatures and resist oxidation and corrosion. Different grades of stainless steel are used depending on the part of the exhaust system. For example, the hot end uses highly alloyed grades like 309 or 310 stainless steel, while the cold end can use type 304 or ferritic type 409. These stainless steel products ensure high strength and durability in automotive exhaust systems. Ready to elevate your automotive and transport projects with high-quality stainless steel? Register with us today to explore our extensive range of stainless steel products.

• Structural components:
  

Stainless steel is increasingly considered for structural applications in vehicles. Its high tensile strength and excellent crashworthiness make it suitable for parts like chassis, suspension, and body structures. Grades like AISI 301l, known for its work-hardening properties and high tensile strength, are beneficial. The dynamic strain rate sensitivity of stainless steel enhances its ability to absorb energy during impacts, improving passenger safety. Stainless steel structural components also benefit from a high strength-to-weight ratio, which is crucial for automotive applications.

• Fuel tanks:
  

With stricter environmental regulations, stainless steel fuel tanks are becoming more popular. They do not leak, absorb vapours, require protective coatings, and can be fully recycled. New manufacturing processes like hydroforming allow these tanks to be shaped into complex forms to fit tight chassis spaces, enhancing fuel efficiency and making them cost-effective solutions.

• Miscellaneous parts:
  

Stainless steel is used in various small automotive parts, such as hose clamps, head gaskets, pump bodies, heat shields, windscreen wipers, airbag containers, and seatbelt springs. These applications benefit from stainless steel's corrosion resistance, manufacturability, and mechanical properties. The visual appeal, quality, and durability of stainless steel products make them ideal for numerous automotive components.

Future developments:

The automotive industry is exploring using stainless steel in new applications, including all-stainless catalytic converters, which could be lighter and more efficient than current designs that use ceramic substrates. The ‘Space frame’ concept involves a tubular framework and is another innovative use being developed. These advancements will further enhance the lifecycle and performance of automotive components.

Transport industry

• Railway applications
  

Stainless steel has a long history in railway applications, dating back to the 1930s. It is used for passenger rolling stock, high-speed, and commuter trains. Its durability, low maintenance, and excellent mechanical properties make it ideal for these applications. Modern examples include Sweden's x2000 high-speed train and France's Ter regional trains. Stainless steel's crashworthiness and fire resistance are critical for passenger safety in rail transport. The lightweight and high-strength properties of stainless steel improve the fuel efficiency and lifecycle of railway vehicles.

• Bus bodies
  

Stainless steel is increasingly used in the structural frameworks and body panels of buses and coaches. This is especially prevalent in Europe, where manufacturers are moving towards fully using stainless steel in bus construction. The material's corrosion resistance and easy maintenance reduce life cycle costs and improve passenger safety by eliminating weak points in the vehicle structure. The weight ratio of stainless steel components contribute to the overall performance and safety of buses.

Advantages over other materials

Mechanical properties: unlike carbon steel, stainless steel offers superior mechanical properties such as better tensile strength, ductility, and hardness. This makes it a more reliable material for critical automotive applications.

Cost-effective: while initially more expensive, stainless steel components' longevity and reduced maintenance needs make them cost-effective in the long run.

Wide temperature applications: stainless steel can operate effectively over various temperatures, making it suitable for multiple automotive applications, including those exposed to high heat or sub-zero conditions.

Grades of stainless steel used

• Ferritic stainless steels: often used in automotive exhaust systems due to their good corrosion resistance and lower cost. They have an FCC structure with 11% to 22% chromium, resulting in magnetic properties, corrosion resistance, and no need for heat treatment.
  

• Martensitic stainless steels: known for their high strength and hardness, they are suitable for applications requiring wear resistance. The body-centred tetragonal structure, characterised by high strength and hardness due to a carbon content ranging from 0.1% to 0.2%, can be subjected to heat treatment with chromium levels between 11% and 18%, resulting in relatively low corrosion resistance.
  

• Austenitic stainless steels: the most widely used type in the automotive industry due to their excellent corrosion resistance, formability, and high-temperature strength. This is a non-magnetic material, highly malleable, and resistant to corrosion due to its nickel (6% to 22%) and chromium (16% to 26%) content. It also has low to medium carbon content.

In the automotive industry, ferritic, martensitic, and austenitic stainless steels are commonly used, with austenitic stainless steel particularly favored for its excellent corrosion resistance and high-temperature strength. Stainless steel contributes to fuel efficiency by reducing the overall weight of the vehicle due to its lightweight components. It is preferred for exhaust systems because of its high resistance to corrosion and ability to withstand extreme temperatures, ensuring durability and longevity. Although stainless steel components may have a higher initial cost, their longevity and reduced maintenance needs make them more cost-effective over time. Additionally, the high strength-to-weight ratio of stainless steel allows for lighter vehicle designs without compromising safety, enhancing both performance in automotive applications.

Market and industry trends

Jindal stainless and share prices: companies like Jindal stainless play a significant role in supplying high-quality stainless steel for automotive applications. The share price and market trends of such companies can be indicative of the industry's health and investment potential.

Innovation in manufacturing processes: advances in manufacturing processes, including the development of new stainless steel grades and surface treatments, continue to drive the use of stainless steel in automotive applications.

Future outlook

The future of stainless steel in the automotive and transport sectors looks promising, with ongoing research into new alloys and manufacturing techniques that promise to enhance the material's properties and applications further. As the industry moves towards more sustainable and efficient vehicles, the role of high-performance materials like stainless steel will become increasingly critical.

In summary, stainless steel's unique combination of properties makes it a vital material in the automotive and transport industries. It offers benefits that extend from performance enhancements to cost savings and environmental sustainability.