Grade 350 Steel And Beyond – Knowing Your Steel Plate Grades

Do you know what grade 350 steel means if someone were to ask you? Do you know the different types of strengths and steel grades available and their different applications? If not then please read on to find out more.


If you are not well acquainted with construction, and the applications of different grades of steel, it can be difficult to know what to order from your steel supplier. In this article we are going to address the different types of steel grades and steel strengths head on in a practical manner for beginners.


In the following article we will overview some of the more common structural steel grades and provide links to more detailed information on the different types of steel grades from Australian steel supplier BlueScope Sheet Metal Supplies.


What are some of the most common grades of steel?


There are a variety of steel grades available that will match different types of projects. For example you may wish to find a mild steel alternative or you may be in need for stronger and tougher steel. Each type of steel comes with benefits and negatives when it comes to employing it in your next project.


Below we will outline some of the most popular and common grades of steel and the different properties and applications that they all have.


Mild Steel Grade 250


If you are looking for a medium strength structural steel plate products, then we recommend the grade 250 mild steel option. This product has a nominal yield strength of 250 MPa.


Mild steel grade 250 steel is used in a variety of industries and for a variety of purposes, including: general fabrications, high-rise buildings, storage tanks, structural members and even bridges.


Mild steel grade 250 is also known by several other names, including: MS, MS 250, Mild steel, or even Grade 250. If you are looking for more information of Mild Steel grade 250 then we recommend you get in contact with your local steel supplier to discuss options further.


Mild Steel Grade 350


When it comes to a stronger alternative to mild steel grade 250, then we recommend grade 350 mild steel as superior structural steel plate product in terms of strength. Mild steel grade 350 steel has a nominal yield strength of 350 MPa.


This type of mild steel is often employed in projects where above average strength is needed without compromising weldability and ductility. Some of the common applications for this grade of steel include: structural members, high rise buildings, bridges, storage tanks and general fabrication.


As such, mild steel grad 250 is often considered a staple of most construction projects, and is often referred too simply as MS 350, or as Grade 350. If you are looking for more information on this product, then we recommend you reach out to your closest metal steel supplier and discuss this grade of steel over other options.


Duraflex K1042 (Steel Grade 1042) or K1045 (Steel Grade 1045) Steel


Duraflex K1042 and Duraflex K1045 are both easily treatable plate grades for several general engineering applications. Duraflex K1042, or Steel Grade 1042, is any type of steel sold and used in Australia or New Zealand. However, due to separate standards, Duraflex K1045, or Steel grade 1045, refers to any type of Duraflex that is sold globally outside of Australia or New Zealand.


Some of the typical applications of this type of grade of steel might include: general engineering parts, profile cut gears, and even wear or abrasion applications.


Due to its popularity, Duraflex K1042 (Steel Grade 1042) and K1045 (Steel Grade 1045) Steel are both known colloquially as either: Dura, Duraflex, K1045 or even K1042. For more information on this product, please refer to your local metal steel supplier to find out if this product is right for your next project.


Boiler Plate Steel (AS 1548-7 460 NR)


If you are looking for maximum tensile strength over any other quality, then you should look no further than the fully killed, fine grained, carbon-manganese steel known as boiler plate steel. This steel has an astounding minimum tensile strength of 430 MPa.


Some of the typical uses for Boiler Plate Steel includes applications in boilers, pressure vessels as well as vessels where welding plate is required (any plate that is weldable in other words).


Boiler plate steel is very common, but is typically only referred to as Boiler Plate Steel. For more information on Boiler Plate Steel, we recommend you reach out to your nearest steel metal supplier to find out more.


Bisalloy Steel – Grades 80, 400 and 500


Previous types of steel discussed cannot compare to the high-strength, low alloy steel plate of Bisalloy steel. Bisalloy steel’s grades range from 80, 400 and 500 and have up to three times the nominal yield of regular carbon steel. Bisalloy steel is low carbon, high quality notch toughness, excellent weldability and great formability.


In order to achieve such high yield tensile strength, Bisalloy steel is quenched and tempered. This plate results in the following grades of steel with the following sets of typical tensile strength:


  • Bisalloy Grade 80 steel has general tensile strength of 830 MPa
  • Bisalloy Grade 400 steel has general tensile strength of 1320 MPa
  • Bisalloy Grade 500 steel has general tensile strength of 1640 MPa


Some of the typical applications of this type of steel include the following: mining equipment, excavator buckets, bridges, transport equipment, lining equipment, deflector plates, earthmoving buckets, dump truck wear liners.


Sometimes Bisalloy is referred to by other names, including: Bis, Bis 80, Bis 400 and Bis 500. For more information on Bisalloy steel products, we recommend you speak to BlueScope steel supplier for more information.


Floor Plate (AS/NZS 3678-250)


Floor plate steel is steel that has been hot rolled and has an expected minimum tensile strength of 250 MPa and is known for its raised surface on one side to avoid slippage. Floor plate is typically just known by it’s name of floor plate steel. It is typically available through most suppliers.


Some Common Terms Explained


There is a lot of terminology involved in the steel industry from descriptions of the steel to the type of steel that is being referred to. In the followings section we will address a few of the key terms used in reference to steel grades.


Mild Steel


Mild steel is a very common term used in the steel industry. However, it is often misunderstood. For one thing, mild steel is not an actual grade. Sometimes ‘mild steel’ is used interchangeably with ‘250 grades’. Although the two are not the same, the reason for this confusion is that 250 grade steel is often purchased made with mild steel. After all, not all mild steel is 250 grade and not all 250 grade steel is mild steel.


In a practicable sense, mild steel actually refers to any low-strength, carbon steel with a carbon level less than 0.2 per cent. There are no specific restrictions on the chemical makeup of carbon steel, the tolerances and quality are not covered in the name either. It is therefore a very broad term to be used.


It is important when purchasing to be more specific about the grade and strength required when ordering and not to just ask for ‘mild steel’.


Silicon Content


Australian steels in general have very little silicon content. Coil plate steel, however, may contain lower silicon amounts than plate steel from a plate mill. Coil plate is therefore generally considered a better alternative for galvanising – especially is the outcome has to be aesthetically please. Less silicon results in a brighter finish when galvanised.


Standard Variations


There are two standards in Australia and New Zealand, and these are AS/NZS 3678 and AS/NZS 1594. These two types of standards differ in terms of dimensional tolerances, strength and surface quality. When referring to BlueScope steel, AS/NZS 3678 refers to 350 XLERPLATE® and AS/NZS 1594 – HA350 XLERCOIL® grades.


These two standards differ in terms of tolerance, thickness, width and flatness. If the attributes are critical, then you must consult the standard AS/NZS 1365.


Within AS NZS 3678 alone, there are different strength requirements of any 250 grade steel product. As thickness increases, the minimum yield strength required for XLERPLATE® decreases. When it reaches 5mm thickness, the yield strength is atlas 280 MPa. Thickness greater than 80mm means atlas 230 MPa.


There are no variations for coil plate however. For AS/NZS 1594-HA250 XLERCOIL® coil plate steel has a maximum yield strength of 250 MPa compared to the full thickness range covered in the standard.




In this article we have looked over the different types of steel grades and strengths and tried to identify key terminology used within the industry. For each steel grade and strength there are corresponding benefits and flaws.


We hope that you have found the above article helpful. For more information on purchasing steel we recommend that you get in contact with your local metal steel supplier.

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