To give the full title: API Specification 20F: Corrosion-Resistant Bolting for use in the Petroleum and Natural Gas Industries, latest edition (2nd) May 2018 (Effective date 1 November 2018).

This standard defines the requirements for the qualification, production and documentation of two of the three BSL (bolting specification levels) defined in API 20E (Alloy and Carbon Steel Bolting for Use in the Petroleum and Natural Gas Industries) – the two higher levels of BSL-2 and BSL-3.

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For information, BSL-1 is the basic that every fastener should adhere to. Manufacturers that produce BSL-1 compliant fasteners show that they produced their fasteners according to specification. Really, all fasteners should be able to comply with BSL-1. BSL-2 builds on BSL-1 and adds additional requirements to perform testing of material, heat treatment, chemistry, mechanical properties, metallurgy, hardness and NDE to ensure bolt integrity. BSL-3 adds to the testing specified in BSL-2 and limits the testing methods that can be used and prohibits fasteners from being made of continuous cast material. BSL-3 fasteners are therefore proven to have been manufactured to very high levels of reliability and integrity, but this means that they are also much more expensive than BSL-1 or BSL-2 fasteners.

API 20F applies to bolting manufacturers (defines as an organisation that through the use of manufacturing equipment and processes appropriate for the bolting product form, transforms raw material into finished bolting). Therefore, this standard does not apply to firms who trade or buy in finished bolting, nor stockholders. As definition 3.1.12 says “a distributor is not considered a raw material supplier” (only a melting mill where raw material is manufactured to be used in qualified bolting is regarded as a raw material supplier).
 

So why is Broder Metals Group Ltd, a speciality steel stockholder not a melting mill, interested in API 20F?

 

Three Reasons:

1. We like to keep abreast of what is happening in our customers’ technical world as well as our own.

2. The API specification only applies to three levels of raw material:
a. Precipitation hardened nickel-based alloys in accordance with API 6ACRA – e.g. alloy 718 – that we stock.
b. Precipitation hardened austenitic iron-based ASTM A453 Grade 660 class D – e.g. Alloy 286 / 660 grades A & D – that we stock.
c. Cold reduced only, or cold reduced and high temperature aged heat-treated condition cobalt-based alloy UNS R30035 – e.g. better known by its trademark names MP35N™ – SPS Technologies LLC / Latrobe Speciality Metals / Carpenter Technology Corporation – and ATI 35N™ – ATI Speciality Metals – and for aged material only in the “NACE” condition – that we stock.

3. Because we stock all three grades, many of our customers started to ask for material we supply to be qualified to “API 20F”. As a quotation requirement, we need to understand what type of qualification we are looking for.

The specification lays the onus on the bolting manufacturer to qualify the (mill) raw material suppliers they use – section 5.1 is the area to read in detail, but summarised points are:

a. Raw material sources must be approved by the bolting manufacturer.
b. The bolting manufacturer must have a procedure for qualifying raw material suppliers for each grade and heat-treated condition of material.
c. The approval process must be based on a quality assurance evaluation and technical evaluation.
d. The approval process must be carried out by a person or organisation with technical authority (i.e. one that is competent and technically qualified, and which has the expertise, skills and experience regarding both quality and [mill] manufacturing processes necessary to perform the verification).
e. For BSL-2 bolting, the technical approval should be by 3 out of 4 approval methods: full inspection of incoming material, raw material first article inspection, demonstration of technical capability or on-site technical audits to mill raw material manufacturers at a minimum of 3-year intervals.
f. For BSL-3 bolting, all 4 of the above must be used.

The specification also covers (5.2) qualification of suppliers for subcontracted operations, (5.3) material specifications, (5.4) manufacturing processes, (5.5) raw material, (5.6) chemical analysis, (5.7) mechanical properties, (5.8) metallurgical requirements, (5.9) hardness test requirements, (5.10) NDE requirements, (5.11) dimensional inspection and visual inspection and (5.12) final PMI.

A full list of API 20F approved, applicant and withdrawn manufacturers can be found by searching at https://mycerts.api.org/Search/CompositeSearch.

There are currently 27 active and applicant organisations on the API register, with the USA leading the way (8 active) with the UK having 3 active and 4 applicants (and 1 withdrawn). China has 1 active and 2 applicants. Italy has 2 active, while Brazil, France, Malaysia, Mexico, Singapore and South Korea have 1 active bolting manufacturer on the register each.

Obviously when we first started getting requests for “20F” material we had to ask our customer who they had qualified so we could quote accordingly. Similarly, we asked our mill suppliers who had qualified them. It was more difficult to get this information than we thought, and we did find some difference of opinion on what the roles within API 20F are. We also found some disparity between how mill qualification had (or was intended to) take place, and how many mills were not aware of the requirement to be approved.

We also came across some divergence of views: “it is a worthwhile attempt to ensure that critical bolting is manufactured correctly”, “it is an attempt by large bolting manufacturers to impose cost on or exclude smaller manufacturers”, “if fastener manufacturers do not have the technical expertise or understanding to evaluate mill manufacturing processes they should not be producing critical level bolting”, “too many fastener manufacturers are listed as applicant rather than going for full active status (implying that they would not be approved, but are on the list), “mill is happy to receive audits as long as there is a commercial benefit”, “mill is not happy to reveal technical IP to multiple third parties every three years – prefer to conduct the process themselves with industry experts independent of the mill”).

At Broder, we spend hours every day evaluating material on stock against international standards and customer specifications to ensure that our material either conforms or to determine what testing may be required in order to conform (whether under our own review or utilising independent third parties with intent of 3.2). We understand and appreciate the need for standards. We appreciate that we are not involved under API 20F and can only supply material from mills approved by our customers. For us this is just another level of qualification that we need to check for before we quote.

However, our natural approach is to see how we can help our customers. So, we embarked on an exercise to understand both what our customers intensions towards qualifying mills and what our major mill suppliers’ attitudes were towards API 20F approval by our customers. Where necessary we tried to bring these two parties together, to ensure that critical bolting is manufactured to the highest possible standard while ensuring that our customers have the widest possible range of competitive quality mill supply available.

To summarise, API 20F is a bolting standard that requires manufacturers of bolting in API 6ACRA, ASTM A453 grade 660 or UNS R30035 material to consider and qualify every aspect of their manufacturing process, including approval of the raw material mill producer. For BSL-3 bolts at least the latter must be by on-site technical audit of every mill they want to use for raw material at a minimum of 3-year intervals.

As a stockholder of those 3 types of material, we have tried to help by bringing together the bolting manufacturer with the appropriate mill, and we will be happy to continue to do so with any other aspirant API 20F fastener manufacturer in the future.

To discuss any of the points raised or If we can help in any other way, please let us know.

To make an enquiry on our stocked API 20F material, contact us on 0114 232 9240.
 

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