What is 430 Steel:Properties, Strength, Uses and Application?

What is 430 Steel?

Everyone has heard about steel and its strength, but far fewer people know about how many different types of steel exist. There are hundreds of steel types available thanks to the alloying process – that is, the ability to blend a base metal with other metallic elements to increase strength, resistance to wear, conductivity, and to provide other improvements to the metal’s physical properties. Steel benefits from many different alloying elements, but one of the most popular elements is chromium which reduces steel’s weakness to corrosion. These chromium alloy steels, known colloquially as “stainless” steels, are all around us in the modern world and are used in everything from kitchenware to medical devices and more. This article will focus on 430 stainless steel, a highly popular material that is perhaps the most famous of the stainless steels (although that title is highly contested). 430 stainless steel’s makeup, properties, and uses will be explored in this article to give readers some idea as to why this material is so popular, and how they might use it in their projects when considering steel as a choice of material.

Physical Properties of 430 Steel

It can be confusing when initially looking at different steel types, as they all have different naming structures. Some have 4-numbered names, some have 3, others have unique identifiers, and this is due to the various naming indexes created by the American Iron & Steel Institute (AISI) and the Society of Automotive Engineers (SAE). These institutions have given different names to steel alloys based on alloying elements, uses, or even specific applications, but they are often consistent across steels of similar grade. The stainless steels are given 3-digit names, where the first digit represents the type of alloying elements present in the steel; in the case of 430 steel, the “4” means steel that primarily uses chromium in its blend.

430 steel belongs to the ferritic group of steels, which means it has a certain molecular structure unique from other steels (to learn more, read our article on the types of stainless steels). It is magnetic and has a density of 7.8 g/cm3 (0.282 lb/in3). Nominally, the blend of elements found in 430 steel is, by percentage:

<0.12% Carbon

<1% Manganese

<0.04% Phosphorus

<0.03% Sulfur

<1% Silicon

and 16-18% Chromium

Type 430 steel is less costly than any of the 300 series steels, as it contains no nickel or molybdenum. It is considered a low carbon, non-hardenable steel, meaning it cannot be strengthened using the heat treatment process, though it does respond to solution annealing. 430 steel can be welded (though it is limited and should not be used for load-bearing applications), is easily machined when in bar form, and prefers to be cold worked when fabricated into its final shape.

Corrosion resistance & temperature effects

Ferritic steels are exceptionally resistant to stress corrosion cracking, and also have good resistance to organic, nitric, phosphoric, and acetic acids. 430 can be bought as 430F stainless steel, which is a free-machining steel resistant to pitting and crevice corrosion effects.

An interesting facet of type 430 steel is how it performs at different temperatures. In high heat environments, 430 steel is capable of withstanding oxidation but tends to turn brittle when cooled from these elevated temperatures. Also, most ferritic steels often fail in brittle fracture when in sub-zero temperatures, meaning that 430 steel is unsuitable for low-temperature applications.

 

Table 1: Summary of mechanical properties for 430 steel.

Some basic mechanical properties of 430 steel are shown above in Table 1. This section will detail each value and how they relate to the physical properties of 430 steel.

As previously explained, 430 steel is easily deformed and worked, and this can be seen through its ultimate and yield strengths. These values show at what stresses the material permanently deforms and the maximum stress value experienced before fracturing. While type 430 steel is quite strong when stressed in tension (517 MPa / 345 MPa), it falls on the lower end of steel strengths. While this may sound disadvantageous, these lower strengths allow this steel to be plastically deformed with less work and allows the material to be easily cut from stock.

The Rockwell Hardness B scale is one of the many scales available that show the surface resilience of a material. A device will impart a local force on the surface of a material and record when it scratches/nicks/deforms. Each test uses its own hardness tester (known as indentation machines), where various materials are tested and then put on a comparative scale. Hardness is therefore only useful in comparison to other materials on the same scale. For reference, the Rockwell B hardness of copper, a soft metal, is 51; in comparison, 430 steel’s Rockwell B hardness is 85, which shows how resistant this material is while still being at the lower end of steels.

Part of the reason 430 steel is so easily machined is thanks to its modulus of elasticity. This value describes how a material deforms in response to forces and generally indicates how “gummy” or elastic a material is. A high modulus of elasticity designates a material that does not stretch/bend easily, which means it is a stiffer, stronger material. 430 steel has a high elastic modulus (200 GPa), which suggests it does not gum up machine mills when processed, and instead breaks off in pieces which is ideal for machined parts. The best way to machine 430 steel is in lightly drawn bars where it has been strain-hardened slightly, as annealed 430 steel is softer and tends to gall.

The elongation at break of a material describes the ratio of the final length versus the initial length after breakage of a test specimen in a tensile test. In simple terms, it shows the ability of a material to resist shape changes without cracking or fracturing, and measures how much deformation a material can withstand before fracturing. It is a great measure for the general ductility of a material, where a high elongation at break indicates a ductile, tough metal. 430 steel has a large elongation at break at 25%, suggesting it is readily shaped without the risk of brittle fracture and is why 430 steel is so valuable as a forming steel.

Applications of 440 Steel

Type 430 steel is a simple, inexpensive, and widely used stainless steel. While not a front runner in any one category, its combination of heat resistance, ductility, corrosion resistance, and low cost makes it a great general-purpose steel. Also, by modifying its composition slightly, 430F stainless steel can be easily machined, making a great machining alloy. Type 430 steel contests the top spot for the most widely used stainless steel, as it can be used in many applications such as:

• Dishwasher linings,
• Automotive trim,
• Range hoods,
• Drawn/formed parts,
• Industrial roofing & wall cladding,
• Utensils,
• Handling equipment for mining,
• Heat-resisting applications,

and more.

To determine if this steel is right for your job, be sure to contact your supplier and ask them for their opinion. They will have the most up-to-date information on which steel will best fit your specifications and can give you the most relevant information on what is available.

XTJ is a leading OEM Manufacturer that is dedicated to providing one-stop manufacturing solutions  from prototype to production. We are proud to be an ISO 9001 certified system quality management company and we are determined to create value in every customer relationship. We do that through collaboration, innovation, process improvements, and exceptional workmanship.