There are different grades of stainless steel that are available in the market. Although all of them are covered under one roof, each type of steel has its unique characteristics.
Two popular grades of steel that you should know are the 420 stainless steel and 430 stainless steel.
Both the 420 stainless steel and 43 stainless steel are alloys of iron that are competing for your attention. So, what is the difference between the two?
This post has the answer to this question. We are going to dissect the differences between 420 stainless steel and 430 stainless steel.
Definition: 420 stainless steel vs 430 Stainless Steel?
What is 420 Stainless Steel?
Grade 420 stainless steel is a type of stainless steel that high carbon content and low in chromium content. The chromium in this stainless steel can be as low as 12%.
Just like other grades of steel, grade 420 stainless steel can also be hardened through various methods such as heat treatment. Doing this helps this stainless steel suitable for tough applications.
Grade 420 stainless steel has an excellent corrosion resistance property especially when it is well coated through polishing. It is also a ductile metal in its annealed state.
Grade 420 stainless steel is usually compared to martensitic steels as they tend to share numerous properties.
What is 430 Stainless Steel?
420 stainless steel is non-hardened steel that contains a high content of chromium element. This type of steel belongs to the ferritic of steel which is known for high formability and corrosion resistance.
The ability of this stainless steel to resist chemicals make it ideal for various sensitive applications where chemicals are involved. It is also resistant to some acids such as nitric acid.
Grade 430 is usually sold in the bar form and strikes some similarities to the Grade 434. The presence of Molybdenum in this steel is to enhance the corrosion resistance property of this metal.
Composition: 420 Stainless Steel vs 430 Stainless Steel
What are the grades 420 and 430 stainless steel made of? The easiest way to know this is by looking at the compositions of these metals.
The table below shows the chemical composition of grade 420 stainless steel.
Grade C Mn Si P S Cr
420 Min 0.15 – – – – 12.0
Max – 1 1 0.040 0.03 14.
The table below shows the chemical composition of 430 stainless steel
Grade C Mn Si P S Cr Mo Ni N
420 Min – – – – – 16.0
Max 0.12 1 1 0.040 0.03 18.0 0.5
From the tables above it is clear that grade 430 stainless steel has a relatively higher content of chromium metal than the 420 stainless steel. This is the main reason why it is physically harder than the 430 stainless steel.
Corrosion Resistance: 420 Stainless Steel vs 430 Stainless Steel
When subjected to extreme conditions, grade 42 stainless steel is resistant to various corrosive agents such as mild acids, freshwater, foods alkalis. The resistance of this stainless steel is improved by applying a smooth surface finish on it.
However, the corrosion resistance of 420 stainless steel reduces when it is exposed to the annealed conditions. This is the reason why it is always ranked below 430 stainless steel when it comes to corrosion resistance.
On the other hand, 430 stainless steel has near-perfect corrosion resistance. Not only is it resistant to corrosion but also to the cracks which can end up causing corrosion on metals.
420 stainless steel can is capable of resisting even the most notorious chemicals such as organic acid. The resistance can be enhanced further by brushing and polishing the surface of this metal. Hen this is done, the metal will even resist crevice corrosion.
From this comparison, it is crystal-clear that 430 has a better corrosion-resistance property than the 420 stainless steel.
Heat Resistance: 420 Stainless Steel vs 430 Stainless Steel
Between grades 420 and 430 stainless steel? Which one is ideal for high-temperature applications?
The answer to this is based on the thermal resistance of these two types of stainless steel.
Grade 420 stainless steel can sustain a stable heat resistance of up to 650°C. It is not capable of sustaining the temperatures above this. It is likely to experience oxidation for extremely high temperatures beyond 650°C.
Grade 430 stainless steel, on the other, can sustain the temperatures of up to 870° C when used continuously. However, the metal tends to be brittle under room temperature after it has been heated for a long time. This problem can be minimized through annealing.
From this comparison, it is clear that 430 stainless is ideal for high-temperature applications than the 420 stainless steel.
Fabrication: 420 Stainless Steel vs 430 Stainless Steel
Both 420 stainless steel and 430 stainless steel must be fabricated when making parts and products.
420 stainless steel is the softer of the two that can be easily fabricated into the desired shape and geometry. It has a relatively lower hardening rate and work. It is also more ductile than the 430 stainless steel.
Although 430 stainless steel can also be fabricated, it has a relatively lower ductility rate than the 420 steel. This makes it quite technical to perform vigorous operations during the fabrication process.
Applications: 420 Stainless Steel vs 430 Stainless Steel
What are the uses of 430 stainless steel and 420 stainless steel?
Here are some of the applications of 420 stainless steel:
-For making surgical equipment
-Manufacturing shear blades
-For making needle valves
Here are some of the applications of 430 stainless steel
-Lashing wires and trims for vehicles
-Cabinet panels for refrigerator
-Chimney liners and stove trim rings
What products would you like to create? As you can see, 430 stainless steel is suited for more vigorous applications than the 420 stainless steel.
I hope you now understand the differences between 430 stainless steel and grade 420 stainless steel. You are now in a perfect position to choose the right steel for your parts and products.
In case you aren’t sure about which steel to choose, seek advice from the stainless steel experts. We at Roche Industry are available to offer any relevant advice regarding stainless steel 420 and 430 stainless steel.