300 vs 400 Series Stainless Steel

300 vs 400 Series Stainless Steel- Best Comparison

300 vs 400 Series Stainless Steel

The appealing characteristics and qualities of stainless steel are liable for its profitable character. With over 250 varieties available, a wide range of applications are growing daily.

There are five different varieties of stainless steel, each of which represents a range of grades. Every class combines distinct mechanical qualities with its chemical composition. 300 series stainless steel is austenitic, and 400 series stainless steel is ferritic with martensitic qualities. The austenitic grade represents 300 vs 400 Series Stainless Steel denotes ferritic with martensitic stainless steel.

300 Series Stainless Steel

A family of iron-based chromium-nickel alloys with corrosion resistance is known as the 300 series austenitic stainless steels. They are frequently used in plumbing system construction due to their exceptional formability, resilience to wear, and strength at varying temperatures. The alloys differ slightly but purposefully from one another. There is sometimes a better option, even if they can be used interchangeably in many situations. In certain circumstances, replacements may result in shortened service lives.

The nine distinct alloys that are included in the 300 series stainless are 304, 309, 310, 316, 317, 318, 321, 330, and 347. That being stated, the 300 series stainless steel alloys 304 and 316 are the most commonly utilized.

400 Series Stainless Steel

The 400 series stainless steels are primarily composed of iron, much like all other steels, but they also contain between 11 and 27 percent chromium, about 1 percent carbon, and a maximum of 2.5 percent nickel as other elements. The hardness and strength of these steels, which have mostly martensitic structures, differ greatly. Although these stainless steels are tougher and frequently provide a better answer than the 300 series, their corrosion resistance is not as good. This depends on the conditions the alloy must tolerate. It’s critical to take into account the basic characteristics, resistances, and operating techniques of each type of 400 series stainless steel while selecting the ideal one for the job.

Difference Between 300 & 400 Series Stainless Steel

The amount of nickel in the alloy is the primary distinction between stainless steel from the 300 and 400 series. One important clue that a stainless steel alloy belongs in the 400 family is the absence of nickel. The 400 series stainless steel is significantly less corrosion-resistant than the 300 series due to the absence of nickel in its composition. All stainless steel alloys, however, are resistant to corrosion; some are only more so than others. The 400 series magnetic feature is another important distinction between the 300 series and 400 series:

1. Corrosion Resistance 

The chemical composition of the various alloy grades that come under each series determines how resistant it is to corrosion. The austenitic class 300 series stainless steel would perform better than the martensitic class 400 series stainless steel, though, if we were to compare the two series together. There are various explanations for this. First off, the 300 series contains a significant amount of nickel and chromium, which increases the alloy’s resistance to corrosion. These steel alloys are more susceptible to rust corrosion because the grade 400 series has a comparatively lower alloying level.

In addition to nickel, the 400 series contains trace amounts of sulfur, phosphorus, manganese, and other elements that, while beneficial, do not significantly improve the alloys’ ability to withstand corrosion. However, the increased carbon content improves its wear resistance characteristics.

2. Chemical Properties

Stainless grades in the 300 series typically include molybdenum, nickel, and chromium. The fundamental components of stainless steel grades of the Grade 400 series are manganese and chromium. While the 400 series has a higher carbon content, the range of chromium concentration appears to be 18–30% for the 300 series and 11–12% for the 400 series.

3. Magnetic Properties

The magnetic grain structure of stainless steel is caused by chromium, one of the alloying elements. Nickel is another potential alloying element that hinders or lessens magnetic characteristics. Because the 300-series stainless steels contain different amounts of nickel, the majority of them are not magnetic. The 400-series stainless steels are mildly magnetic and have a grain structure resembling carbon steel. They also don’t include nickel.

4. Pricing 

In a straight cost comparison, stainless steel 304 costs around 50% more than stainless steel 410 (although 316 is more expensive than both). As a result, most 300-series fasteners are typically msies equivalents. Therefore, if there is little chance of contact with corrosive elements, we frequently recommend 400 stainless steel to our consumers.

However, we advise customers to consider the long-term savings that come from fasteners with inherent resistance to rust (304 or 316) rather than those that will impair the integrity of the build in scenarios where external corrosive elements would be present in high concentrations. 

Pros and Cons of 300 and 400 Stainless Steels

300 Series Pros

  • Superior resistance to corrosion in comparison to stainless steel in the 400 series.

300 Series Cons

  • More costly up front than stainless steel fasteners from the 400 series.

400 Series Pros

  • Less expensive than stainless steel fasteners from the 300 series.
  • Stronger and harder than stainless steel from the 300 series.
  • Enhanced functionality at higher temperatures.

400 Series Cons

  • Weaker corrosion resistance than stainless steel in the 300 series.

300 Series And 400 Series Features & Specification

MACHINABILITYExcellentBad/Gummy: won’t maintain a brilliant finishGood
STRENGTH OF STEELExcellentPoor / Not heat-treatable to hardenGood
SHOCK RESISTANCEExcellentExcellentGood


All things considered, the composition, characteristics, and uses of stainless steel belonging to the 300 and 400 series differ considerably. Since the 300 series has a high nickel content, it is ideal for demanding applications in a variety of sectors due to its exceptional ductility, weldability, and corrosion resistance. Structural components and other areas where corrosion resistance is less important find use for the 400 series due to its higher strength and cost-effectiveness.