What grade of steel should i use

High ductility is indicated by a high percentage e. The need for Z-grade steel Improvements in steel manufacturing over the years mean that steel from modern mills is much cleaner, and less likely to contain significant levels of micro imperfections than in the past.

The through thickness ductility of such steels is sufficient for most applications, and is typically equivalent to Z15 or Z25 material. Hence, there should be very little need to specify Z-grade steel in typical well-designed bridge steelwork. Z-grade steel might be required where high loads are transmitted through T-section or cruciform details, and where large welds are specified on elements that are restrained against shrinkage. Guidance Note 3.

However, the requirements for Z-grade steel are usually very local in nature, and as such only small quantities will be needed. Additionally, Z-grade steel is more expensive and less readily available than conventional structural steel. Consequently, it is better to design details that do not require the use of steel with improved through thickness properties, if possible. Which Z-grade to specify? EN [14] contains a numerical method for determining the required Z-grade according to the weld size, detail type and level of restraint.

However, the UK NA [15] indicates that this need not be used. The view of the UK experts is that this numerical method is unduly conservative, requires extensive calculations, and would lead to the unnecessary specification of Z-grade material. Where t z is the thickness of the incoming plate for butt welds and deep penetration fillet welds, and for fillet welded joints, t z is the throat size of the largest fillet weld.

This clause in EN [3] merely states that rolled steel products should conform to the tolerances in the relevant product standard and that for fabricated components the tolerances in EN [4] should apply. The material coefficients to be used in the design calculations for steel bridges are:. The general availability of structural steel sections for bridgeworks is outlined in the following British Steel and Tata Steel product brochures:. Plates are readily available in a wide range of sizes and material grades in the UK, and may be obtained either direct from the mill, or through a steel stockholder.

The advantage of obtaining plates direct from the mill is that they are rolled to order, specifically to a chosen size, which minimises waste and maximises design efficiency, as any intermediate thickness is available.

Web and flange plates are generally procured through this route, so maximum efficiency is achieved by specifying the actual thickness required according to the design calculations.

Rounding up to the nearest 5mm is not advisable as it merely increases the cost of the steelwork. Normal plate sizes range from 5mm to mm thick, with widths up to 3.

Steel from a stockholder is more suited to small quantities, and will reduce lead times. However, it will be more expensive, and the size and quality required may not be readily available.

It is important to trace the source of the steel and obtain the appropriate mill certificates. Typical stock sizes are illustrated below, and thicknesses are generally in 5mm increments.

Plates for stiffeners are typically procured from stockholders, so the thickness of stiffeners should be rounded up to the nearest 5mm. The execution standard for steel bridges designed to the Eurocodes is EN [4]. It includes requirements related to the supply of products and refers to the appropriate product standards for their specification. EN [4] has numerous provisions where additional requirements or decisions on optional requirements may be specified; some of these relate to the steel products.

Different projects will almost certainly have different execution specifications, but the use of standard specifications, such as the Specification for Highway Works [23] , is recommended to ensure consistency across the industry. The following sections describe the key requirements relating to steel products that are specified in either EN [4] and its reference standards or in the Specification for Highway Works [23].

Note that Network Rail's Specification for structural steelwork [24] has similar requirements. A record should be maintained of the source of, and test certificates for, main structural steel elements including each flange and web in order to provide traceability.

This requirement is implemented by the Specification for Highway Works [23]. The chosen grade s of steel are specified to the standards listed in EN [4] and the grade and sub-grade should be stated on the drawings.

Guidance on the specification of tension bar components is available in Guidance Note 4. The thickness tolerances in Class A increase with the nominal thickness as follows:. Although steel is visually inspected before it leaves the mill, it is not usually blast cleaned and still has mill scale adhering to it. Consequently, the surface that is revealed after grit blasting may show surface discontinuities that were not visible before. For plates, Class A means that shallow depth imperfections are acceptable, but defects, including cracks, shell and seams, must be repaired i.

Stainless steel falls into four distinct families:. But the family is only part of the story. You can find a full list of common identifiers here. For example, stainless steel by the SAE standard might also be graded as:. However, to receive a given grade designation, the alloy must adhere to a strict set of requirements set forth by the organization maintaining the standard.

When you pair a family and grade together, you get a good indication of what to expect from a specific stainless steel alloy. You can learn about everything from magnetism and toughness to corrosion resistance and heat resistance.

While there are too many types to individually list, these general classifications provide an idea of what to expect within each family as well as common grades requested. While austenitic stainless steel is non-magnetic when annealed with a solution, certain cold worked grades are magnetic.

Heat-based hardening will not work with these types of steel. We are metal experts and have been providing quality customer service and products since At Metal Supermarkets, we supply a wide range of metals for a variety of applications. Our stock includes: mild steel, stainless steel, aluminum, tool steel, alloy steel, brass, bronze and copper.

We stock a wide range of shapes including: bars, tubes, sheets, plates and more. And we can cut metal to your exact specifications. See all Blog Posts. Does the carbon steel need to be welded? What are the strength requirements of the carbon steel? Does the carbon steel require good formability? Does the carbon steel need to be heat-treatable? Does the carbon steel need to have good corrosion resistance?

What applications do you need the carbon steel for? Does the carbon steel need to be machined? Tool steels, as you can probably guess by the name, excel in cutting and drilling equipment. The secret is the tungsten, molybdenum, cobalt, and vanadium that increases their heat resistance and overall durability.

And since they retain their shape under heavy usage, they're the go-to material for most hand tools. Steel grading systems give us a way to categorize steel types based on all the different uses that make them distinct. For instance, the rate that manufacturers cool steel can impact how strong it is on a molecular level. The amount of time they keep steel at critical temperatures during the cooling process plays an important role as well. In fact, it's possible for two sheets of steel with the same alloy content to have different grades based on their heat-treatment process.