A105 is an ASTM material widely used in forged flanges. It is the one that demands the least mechanical characteristics; in other words, it is the most utilitarian steel used in flange manufacture. As ASTM, it does not require any mechanical characteristics beyond those derived from the tensile and hardness test. It is not a material used in midstream pipelines, but it is used in refineries and other downstream facilities.
The use of A105 forged flanges in industry
In industry in general and in the oil & gas industry in particular, A105 has been a very controversial material, as the standard requires one thing and customers, end users in particular, assume another. In general, this material does not require mechanical characteristics beyond those indicated above, but there is a belief or assumption on the part of end users that it must meet other requirements that are not indicated in the intrinsic characteristics of the material itself.
This assumption is based on design standards that allow this material to be used at low temperatures without a resilience test. No one knows why this is so, or how or when it was defined this way. However, it is preferable not to modify these standards, although in recent times they have added a condition that the raw material must comply with: it must be steel that has been enhanced with grain refining practices (fully killed and Fine Grain Practice). This improved material involves, on the one hand, the addition of elements such as aluminium, silicon and other elements to deoxidize the steel by adding alloys such as silicon, manganese and/or aluminium (fully killed). On the other hand, alloying elements such as aluminium are added to the raw material, which has two effects: deoxidizing the steel and refining the grain, or not allowing the grain size to grow.
In view of this, and knowing that since 2014 all of the material purchased is fully killed and uses Fine Grain Practice, ULMA Forja has taken a step forward in the market and offers a material that exceeds what the standard requires and that responds to the end user’s need for the characteristics that A105N should comply with, yet the standard does not mention.
Maximum quality and performance in A105
The standard material offered by ULMA complies with all the characteristics of the applicable standards, those proposed by some end users, and the most demanding specifications of some projects and client specifications. It offers clean materials with low sulphur and phosphorus and high manganese content, far exceeding the Mn/C ratio of 5 that some indicate is the minimum necessary. This translates into the best mechanical characteristics and highest resilience on the market.
The resilience values obtained and not required by the standard are in 3 digits in most cases, when our internal acceptance criterion is 27 joules. The end users who we have spoken to in this regard have indicated that it is a very good practice that comes to fulfill what they expect from their suppliers.
So today, ULMA Forge’s A105N flanges are made with Fine Grain Practice and fully killed material, and manufactured with the best forging practices. This places them well above the standards of the A105N flange market and gives end users the peace of mind they are looking for.