Filler Metal Procurement
ASME Section II Part C SFA-5.01
ASME Section II Part C, SFA-5.01 provides various standardized guidelines for procuring welding consumables, when used properly the guidelines enable clear communication of expectations and requirements between purchasers and suppliers.
Selection of the Lot Class (Lot Size), and Testing Schedule (Tests performed on the Lot Class) detailed in SFA-5.01 are dependent on your specific application, quality program, and customer requirements. If testing is required on each heat or batch of filler metal it must be specified by the purchaser and communicated to the supplier. In the absence of any such testing requirements stated in the purchase order, the manufacturer or supplier may ship the filler metal with whatever testing the manufacturer or supplier normally conducts on filler metal of that classification as supported by their quality assurance program (Refer to SFA-5.01 Annex A - A1).
Manufacturers produce welding consumables in discrete quantities. These quantities are known by such terms as heats, lots, blends, batches, and mixes, which vary in size according to definitions established in SFA-5.01 or in the manufacturers quality assurance program. Depending on the applicable requirements actual testing may be performed on the lot you are purchasing, or in most cases the lot you are purchasing includes a “Typical MTR” which is based on testing performed on a representative lot.
DO FILLER METAL MANUFACTURERS TEST EACH HEAT OR BATCH?
The quick answer is that manufacturers do not test each heat or batch of filler metal unless required by the purchaser to do so. To reduce the frequency of tests filler metal manufacturers can establish a reduced testing frequency based on their ability to demonstrate that their manufacturing program consistently meets specification requirements. This reduction in testing to some extent decreases costs of the filler metal, but may not be what was expected by the purchaser. Remember that the specification allows the manufacturer to sell filler metals with certification paperwork that is only representative of that which is being sold if supported by the manufacturer’s quality assurance program (refer to SFA-5.01 Annex A paragraph A1).
In the industry the representative material certification paperwork is commonly referred to as a “Typical Test Report”. The “Typical Test Report” has developed as a non-standard term and may not be consistent between different manufacturers to describe the representative certification paperwork; refer to the definitions section for “Certificate of Compliance” and “Certificate of Conformance” which are formally defined by SFA-5.01.
WHAT IS CERTIFICATION OF FILLER METAL BY REPRESENTATIVE MATERIAL?
The only way to guarantee that you will receive filler metal that has been tested by the lot or heat you are purchasing is to specify it on the purchase order; otherwise the filler metal you receive will be supported by certification paperwork that has been performed on material that represents the filler metal you are receiving (Representative Testing or Typical Testing) and not on the actual filler metal lot (Actual Test Report).
The act of placing the AWS specification and classification designations on the packaging enclosing the product, or the classification on the product itself, constitutes the manufacturer’s certification that the product would meet all the requirements of the specification if it were actually tested, even thought it may not have been tested.
The only testing requirement implicit in this certification is that the manufacturer has actually conducted the tests required by the specification on material that is representative of that being shipped and that the representative material met the requirements of the specification.
Representative material, in this case, is material from any production run of that classification using the same formulation. Certification is not to be interpreted to mean that tests of any kind were necessarily conducted on samples of the specific material shipped.
The basis for the certification required by the specification is the classification test of representative material cited above, and the manufacturer’s quality assurance program in AWS 5.01 of SFA-5.01.
WHAT IS THE FRAMEWORK FOR TESTING OF FILLER METAL?
Step 1: Define the required Lot Class (Lot Size) : see Clause 4 of SFA-5.01
Defines how big of a batch or lot that can be made and still be represented by the testing conducted.
Smaller batches or lots increase the likelihood that the samples tested more accurately represent the material or filler metal produced.
Smaller batches or lots increase testing frequency and increase costs
Step 2: Define the Level of Testing (Tests performed on the Lot Class) : see Clause 5 of SFA-5.01
Select 1 of the testing requirements from the 6 that are defined that match your application.
WHAT HAPPENS IF I DON’T SPECIFY THE LOT CLASS OR LEVEL OF TESTING FOR FILLER METAL?
When nothing is specified by the purchaser the default for the testing schedule is Schedule 1 or F, and the default Lot Size is as defined in Lot Class S1, T1, C1, or F1, as applicable. Testing in accordance with any other Schedule or classification to any other Lot Class must be specifically required by the purchase order. In such cases, acceptance of the material shipped will be in accordance with those requirements.
Any testing a purchaser requires of the supplier, for filler metal shipped in accordance with a filler metal specification, needs to be clearly stated in the purchase order according to the provisions of this specification. Refer to SFA-5.01 Table 2 for specifying required tests by filler metal specification. In the absence of any such statement in the purchase order, the supplier may ship the filler metal with whatever testing the supplier normally conducts on filler metal of that classifications.
Refer to SFA-5.01 Annex B for more detailed explanation.
WHAT NEEDS TO BE SPECIFIED WHEN BUYING FILLER METAL?
Basic* : Specification + Classification.
Advanced : Specification + Classification + Lot Class + Testing Schedule
*When only specifying Specification + Classification on the filler metal purchase order you will receive certification paperwork based on “representative testing”. The testing will be as defined on SFA-5.01 Schedule 1 or F, and the default Lot Size will be as defined in Lot Class S1, T1, C1, or F1, as applicable.
Lot Classification : Clause 4 of SFA-5.01
Level of Testing : Clause 5 of SFA-5.01
FILLER METAL DEFINITIONS
Actual Test Report : a non-standard term referring to the certification paperwork based on the actual filler metal material.
Typical Test Report : a non-standard term referring to the certification paperwork based on a representative material sample. This representative paperwork is considered to be “Typical” and that the product supplied will meet the requirements of the applicable consumable specification if it were to be tested. The use of “Typical Test Report” may not be consistently applied between different manufacturers; refer to the more consistent definitions of “Certificate of Compliance” or “Certificate of Conformance”.
Certificate of Compliance : A statement that the product meets the requirements of the AWS, ISO, or other applicable welding consumable specification/classification.
Certificate of Conformance : A test report documenting that the product meets the requirements of the AWS, ISO, or other applicable welding consumable specification/classification.
MTR : Material Test Report : an MTR is a report documenting the results of tests performed by the manufacturer to fulfill the requirements of the material specification. Results of test performed to meet supplementary or special requirements specified by the purchaser may also be included on the MTR. An MTR shall identify
CMTR : Certified Material Test Report : is a certified MTR, a CMTR is a test report where there is specific references to the tests being conducted on the actual material supplied. The CMTR may contain results of some or all of the tests required for classification, or other tests as agreed upon by the purchaser and supplier.
Heat : For fully metallic consumables, or the fully metallic portion of the filler metal; the material obtained from one furnace melt, or uninterrupted series of melts from one controlled batch that shares the same chemical composition, processing conditions, and traceability.
Batch : a batch generally refers to the ingredients mixed at one time in one mixing vessel, generally to create the flux portion of the filler metal. It is a key concept in ensuring traceability and quality control, particularly for filler metals like covered electrodes or tubular cored electrodes/rods. While not always used interchangeably with "lot," batches form the basis for defining certain lot sizes and classifications.
Lot : a discrete, defined quantity of welding consumables, usually beginning with the word “Lot” and followed by a series of alpha-numeric characters. A lot groups the welding consumables together by a defined quantity that has associated testing performed on it. A lot facilitates traceability back to the testing information that is documented on supporting paperwork such as an MTR or Certificate of Conformance.
Lot Class : is identified in ASME SFA-5.01 Clause 4 and details the rules or requirements for grouping consumables into a single lot.