CHAPTER 2 CRHS-56/70 STEEL PLATE, SHEET, OR COIL
2.4 Production Lot Verification
Production lot verification means the process to verify the conformance of production lots to the requirements of this chapter.
2.2.5 A lot
In production lot verification of production lots , a lot is defined as follows:
(a) For chemical analysis (i) ingot cast, each heat;
(ii) continuous cast, each ladle;
(iii) VAR or ESR (vacuum arc or electroslag remelt), each remelted ingot; and (iv) AOD (argon-oxygen decarburization), each vessel charge.
Note: Unless multiple ladle continuous casting was qualified by works approval testing, continuous casting shall cease after one ladle of steel is completely cast.
(b) For tension tests
Each plate, sheet, or coil as-heat-treated shall constitute a lot.
(c) For impact tests
Each plate, sheet, or coil as-heat-treated shall constitute a lot.
(d) For examination
For purposes of visual and dimensional examination and for nondestructive inspection, each plate, sheet, or coil prepared for final inspection shall constitute a lot.
2.2.6 Heat treatment
Any of the following processes: homogenization/normalization, austenitization, quenching (in any medium), tempering, precipitation hardening, stress relief, and hydrogen soak.
2.2.7 As rolled condition
As rolled condition means that the material is not heat treated after rolling.
2.2.8 Purchase order
A purchase order herein means a document issued by a buyer (e.g., a shipyard) to a seller (e.g., the Manufacturer) indicating product type, grade, and other details of specification or requirements. It is used to control the purchasing of products which shall meet the needs and specification from a seller.
2.2.9 Final rolling direction
For plate, sheet, or coil, final rolling direction is the direction of rolling in which the greatest reduction ratio was achieved.
2.3 Works Approval
2.3.1 General
CRHS steels are to be made at works which have been approved by the Society. In order that works can be considered for approval, the Manufacturer is required to demonstrate to the satisfaction of the Society that the necessary manufacturing and testing facilities are available and are supervised by qualified personnel. When the Manufacturer has more than one work or foundry, the approval is only valid for the individual work or foundry for which the assessment procedure has been carried out.
CHAPTER 2 CRHS-56/70 STEEL PLATE, SHEET, OR COIL 2.3 Works Approval
When steel is not produced at the works at which it is rolled, a certificate is to be supplied to the Surveyor by the Manufacturer stating the name of the steel producer, the process of manufacture, the cast number and the chemical composition of ladle samples, and the steel producer is also to have works approval issued by the Society.
2.3.3 Works approval requirements
A specified procedure of approval of CRHS steels works generally consists of document review, on-site audit and approval test. In addition to the reqirements in this chapter, the works shall also comply with "Guidelines for Survey of Products for Marine Use" of the Society for works approval as specified in Table 2-1.
Table 2-1
Low Alloy Steel for Critical ApplicationDocument Review X X
On-Site Audit X -
Approval Test - X
Note: Required items for works apprvoal of CRHS steels are marked with an "X".
2.3.4 Document review
(a) Submittal
In addition to the documets specified in "Guidelines for Survey of Products for Marine Use" of the Society for works approval, the Manufacturer shall submit a detailed qualification plan to the Society for approval outlining the manufacturing processes and testing proposed to meet the requirements herein. Documented quality system (the latest edition of ISO 9001), process control plan associated with the CRHS steels and a listing of referenced process documents which become part of the process control plan are also to be submitted to the Society for document review before on-site audit and approval test.
(b) Process control plan
(i) The Manufacturer must demonstrate during works approval that it has an adequate process to ensure the specified composition and mechanical properties are met throughout the product. The process control plan shall contain at least the following critical processing procedures:
(1) Melting facility.
(2) Melting method, including refining and degassing procedures.
(3) Cropping practices to ensure all finished material will meet specification requirements.
(4) Casting procedures (as applicable), including molding materials.
(5) Ingot, plate, and casting soaking treatments (as applicable).
(6) Minimum rolling reduction ratios (as applicable).
(7) Heat treatment parameters (temperature, time, cooling method, and atmosphere for intermediate (in process) and final heat treatment).
(8) Heat treatment facilities (which facilities were used, etc.).
(9) Any lubricating, de-scaling, cleaning, or pickling operations used during manufacture.
(10) All processes that could negatively impact the final surface and near surface chemical composition of the delivered product.
(11) A specific change control plan which specifies the criteria and plan to verify the acceptability of any change in the critical processing procedures as listed in the Process Control Plan.
(12) Procedures and processes for removing, machining, preparing, and testing of tensile specimens from first articles, prolongations, and/or test blocks with specific consideration for minimizing hydrogen loss from specimens between removal and testing.
(13) Additional requirements as deemed necessary by the Society.
(ii) Cold cracking susceptibility (Pcm) and carbon equivalent (Ceq)
In addition, as part of the process control plan, the Manufacturer shall identify the maximum Pcm and the minimum Ceq values that will be used during production to provide enhanced resistance to hydrogen-assisted heat affected zone cracking and reasonable assurance of meeting minimum yield strength, respectively. These values shall be based upon available laboratory and production data and shall be reflected in the material submitted for works approval testing. The formulas for determining Pcm and Ceq
are as follows:
All previous revisions must be kept on file for audit, and the version of the process control plan used during manufacture of procured products must be recorded for each delivered lot. The revision record of the Process Control Plan must also indicate any problems that have been identified by the Manufacturer, the Navy, or the Society with their product which required a process control plan revision, including receipt inspection, fabrication, or in service and how these problems were adequately resolved and the necessary changes made in the manufacturing procedures to ensure that these problems will not occur in the future.
(iv) Employees
The Manufacturer shall ensure that employees responsible for manufacturing and testing the approved product(s) understand the appropriate procedures (e.g., molding, heat treatment, nondestructive inspection, mechanical property testing) in the plan. Any amendments/revisions to this plan which could negatively affect the properties of the product must be supported by data and submitted to the Society for review for acceptability. The employee training methods shall be available for auditors when requested. The Manufacturer shall ensure that an up-to-date copy of the Process Control Plan, including any amendments/revisions, is readily available in the work for use by auditors when evaluating compliance with procedures approved by works approval testing and by employees.
2.3.5 On-site audit
(a) When the documents submitted to the Society for the document review are deemed satisfactory, the Surveyor of the Society is to carry out an on-site audit at the work.
(b) The work is to be assessed to ascertain that it is duly organised and managed in accordance with the requirements specified in "Guidelines for Survey of Products for Marine Use" of the Society and submitted documents as specified in 2.3.4 which includes its quality system.
2.3.6 Approval tests
CHAPTER 2 CRHS-56/70 STEEL PLATE, SHEET, OR COIL 2.3 Works Approval
Table 2-2
Examinations and Tests of Approval Tests
Tests and Examination Requirement Test Method Approval Tests
Chemical analysis 2.6 2.9.1 X
Microstructure analysis 2.9.2 X
Weldability test 2.9.4 X
Explosion test 2.9.8 Appendix 1 X
Mechanical Properties
Tensile properties 2.8.1 2.9.3(a) X
Charpy V-notch 2.8.1 2.9.3(b) X
Drop weight nil-ductility 2.8.2 2.9.3(b) X
CTOD test 2.8.3 2.9.3(c) X
Examinations
Surface quality 2.9.5 X
Dimensional tolerance 2.9.6 X
Internal soundness 2.9.7 X
Note: Required examinations and tests for approval tests are marked with an "X".
(b) The manufacture of the first article (e.g., rolling of plate or slabs) for works approval, the laying out of test specimens, and the testing shall be witnessed by the Suveyor.
2.3.7 Renewal audit of works approval
(a) General
For all materials covered in this chapter, renewal audit of the works approval is required every 3 years to verify that the Manufacturer's facilities, processes and manufacturing methods associated with works approval are being maintained.
(b) Request and submittal
Each approved Manufacturer is required to request this renewal audit from the Society to maintain its works approval qualification. The Manufacturer's request shall be submitted to the Soc iety directly with a copy to all procuring activities associated with approved materials where deemed necessary by the Society. This request should be submitted at least 3 months prior to the need for renewal audit. The Manufacturer's renewal audit submittal shall include the following:
(i) A summary of the production lot verification test results (including maximum thickness of product, mechanical properties, re-test results, and chemical composition) on qualified products produced since qualification or the previous renewal audit including production product non-conformances and the associated cause(s) and corrective action(s).
(ii) All production related facility changes on facilities used to produce the qualified product over the past 3 years.
(iii) All process control plan changes over the past 3 years which could affect the quality or performance of the product.
(iv) The change control plan used to adjudicate changes to the process control plan and required related submittals for approval to the Society by the Manufacturer.
(c) Additional requirements
The renewal audit process shall include a review of the Manufacturer's submittal. This may include a request for additional information or data and/or an audit of the facility to review current procedures a nd equipment, if deemed necessary by the Society. Based on the findings of these reviews, additional works approval testing may be required for approval of renewal audit.
(d) Where the renewal audit is not completed before the expiry date of the certificat e, the certificate will be invalidated and the CR Lists of Approved Marine Products will be revised accordingly.
2.4 Production Lot Verification
2.4.1 Production lot verification consists of several examinations and tests as specified in Table 2-3.
Table 2-3
Examinations and Tests of Production Lot verification
Tests and Examination Requirement Test Method Production lotverification
Chemical analysis 2.6 2.9.1 X
Microstructure analysis - -
Weldability test - -
Explosion test - -
Mechanical Properties
Tensile properties 2.8.1 2.9.3(a) X
Charpy V-notch 2.8.1 2.9.3(b) X
Drop weight nil-ductility - - -
CTOD test - - -
Examinations
Surface quality 2.9.5 X
Dimensional tolerance 2.9.6 X
Internal soundness 2.9.7 X
Note: Required examinations and tests for production lot verification are marked with an "X".
2.4.2 Certification of conformance of production lot verification
(a) A certificate of conformance shall be prepared for each lot of material offered for acceptance. The certificate shall include:
(i) actual data of specified chemical and mechanical tests;
(ii) a record of the final heat treatment (if applicable); and
(iii) qualitative results of nondestructive tests and other inspections or tests.
(b) In addition, the certificate shall state that
(i) each lot has been sampled, tested, and inspected in accordance with the requirements of this chapter and that the Manufacturer has maintained adequate manufacturing procedures demonstrated in works approval testing as listed and maintained as specified in process control plan and quality assurance
CHAPTER 2 CRHS-56/70 STEEL PLATE, SHEET, OR COIL