Process Review Checklist

Transcription

1 Process Review Checklist DISCLAIMER. Due to time constraints, the student process review exercise is only a few minutes long. A through, complete process review checklist is not expected as a result but students should demonstrate an understanding of what actions are expected to achieve an adequate process review. In working environment, a contract, technical specifications (both military and industry), supplier s production records, training records, work instructions, inspection records, and actual direct observations of supplier s work performed and Government product examination are expected to be part of a completed process review. During review of process inputs and controls, QA Personnel: Assess inputs against the technical requirements Witness and evaluate process steps/activities and controls in use Perform a product examination to ascertain if the process results meet the specified output requirements SCENARIO You are the QAS working a contract where the supplier, Valley Forgings, is required to use Shielded Metal Arc Welding (SMAW) welding procedure. As a QAS, you must review the supplier's SMAW process (provided) to determine which process element controls require validation during the witness and evaluation stage of process review. The procedure should: Identify important aspects in the correct sequence Have sufficient controls in place Address special skills Be adequate to meet all contractual requirements as noted in the contract Address the five key process elements [Methods, Manpower, Material, Machinery, and Environment (4M&E)] OBJECTIVES Using the provided generic welding checklist, identify requirements to be met. If a clear noncompliance is discovered, identify what doesn t meet the requirement(s) and explain why. INSTRUCTIONS Review the Background information (below) and fill out the Process Review Guideline (Checklist) (CMQ101_M4_L1_E1_Checklist.pdf) provided separately. RESULTS Be prepared to discuss answers as a group with the instructor once the exercise time has expired. 1 Defense Acquisition University

2 BACKGROUND SUPPLIER: Valley Forgings 1665 Lake Norman Way, Suite 300 Colonial, NC Supplier is a reputable source of forged steel products including shipboard plates and pipes used in the vessel propulsion systems. They have numerous concurrent U.S. Navy contracts for a variety of steel products requiring welding procedures (referenced below). PROCESS: Valley Forging Welding process of Carbon Steel Alloys (S-1, and S-11) using the Shielded Metal Arc Welding process (SMAW) manual process. SMAW is an arc welding process that uses a fluxcoated consumable rod electrode. It is also referred to as SMAW or stick welding. Valley Forgings employees Sam Jackson and Wayne Page are the welders assigned to this item. Attached is a record of their qualifications. (A separate complete Procedure Qualification Record is on file for each welder for various welding processes (SAW, SMAC, GMAC, etc.). Contractual Requirements for this process (Process Inputs): NAVSEA S9074-AR-GIB-010/278 - Requirements for Fabrication Welding and Inspection and Casting Inspection and Repair for Machinery, Piping, and Pressure Vessels. NAVSEA T9074-AD-GIB-010/ Requirements for Fabrication, Welding and Inspection of Submarine Structure. MIL-STD 1689A - Requirements for Fabrication, Welding and Inspection of Ships Structure. AWS B2.1/B2.1M, (2009) Specification for Welding Procedure and Performance Qualification. Supplier Procedure Number, Title & Revision Level/Date (Process Inputs): WP-004-NC, SMAW Carbon Steel Alloys, Rev: 3, Dated 05 May 2010 Process to be reviewed Valley Forgings welding process of Carbon Steel Alloys (S-1, and S- 11) using the Shielded Metal Arc Welding process (SMAW) manual process on carbon steel pipes (all positions, groove welds, and socket welds). Scope of Process Review Based on the risk impact rated as high, all process elements were reviewed. Method of review single event, all process elements to be reviewed. QAS to review the SMAW process to determine its adequacy in consistently producing a conforming product. Items being processed at the time of the review: o Nomenclature: S-1 Carbon Steel pipe (MIL-P-24338) o Part number: Various 2 Defense Acquisition University

3 PROCEDURE QUALIFICATION RECORD (PQR) Company: Valley Forgings Approved by: James Smith, QEHS Manager PQR No.: Date: 05 FEB 2013 Employee: Samuel Leighton Jackson Employee no.: 9408 Has been tested and qualified to: Welding Process(es): SMAW, GMAW, GTAW Type(s): Manual, Semiautomatic, Automatic (Manual, Semiautomatic, Automatic, Robotic, Mechanized) Annual Vision test requirement performed: 05 FEB 2013 Qualifications are to be maintained Quarterly i/a/w S9074-AR-GIB-010/248 We, the undersigned, certify that the statements in the attached record are correct and the test welds were prepared, welded, and tested in accordance with the requirements of AWS B2.1/B2.1M, (2009) Specification for Welding Procedure and Performance Qualification. (2013) Manufacturer or Contractor: Valley Forgings Date: 11 FEB 2013 By: James Smith, QEHS Manager James Smith (Please Print) PROCEDURE QUALIFICATION RECORD (PQR) Company: Valley Forgings Approved by: James Smith, QEHS Manager PQR No.: Date: 04 FEB 2013 Employee: Wayne Jonah Page Employee no.: 9311 Has been tested and qualified to: Welding Process(es): GMAW, GTAW, FCAW Type(s): Manual, Semiautomatic, Automatic (Manual, Semiautomatic, Automatic, Robotic, Mechanized) Annual Vision test requirement performed: 04 FEB 2013 Qualifications are to be maintained Quarterly i/a/w S9074-AR-GIB-010/248 We, the undersigned, certify that the statements in the attached record are correct and the test welds were prepared, welded, and tested in accordance with the requirements of AWS B2.1/B2.1M, (2009) Specification for Welding Procedure and Performance Qualification. (2013) Manufacturer or Contractor: Valley Forgings Date: 11 FEB 2013 By: James Smith, QEHS Manager James Smith (Please Print) 3 Defense Acquisition University

4 BASIC SHIP PIPE INFORMATION For reference only The majority of ships pipes are made of mild steel. Flow rate, viscosity, and pressure of fluid being carried determine a pipe s diameter. The water circulating in cooling pipes will corrode them over time. Pipes passing through tanks containing liquid are exposed to corrosive attack on both surfaces. Visual checks of the external surfaces of a pipe will not indicate its condition because it could be internally corroded and have a reduced wall thickness. Most abrasive corrosion and consequent internal thinning happens where the pipe bends and at elbows. Liquid flowing quickly will be turbulent as a result of fluid separation and cavitation. Flow turbulence in a pipe will cause pitting. A pipe with the correct diameter for the job will eliminate turbulence. Pipes can be joined by butt-welding, with flange connections or mechanical joints A pressure test of 1.5 times design pressure is a strength test; a test at the design pressure is a tightness test. Pressure testing can show the small cracks and holes that will not be found by a visual examination. Pipes are held in place by supports or clips that prevent movement from shock loads and vibration. Pipe failure is common when pipes are allowed to vibrate. Pipes are checked visually. A pressure test is done if there is any doubt as to their integrity. Pipes connecting to the shell are subject to particular attention. Pipes are checked visually and hammer-tested, with some pipes also being pressure-tested. The surveyor will select which pipes are to be pressure-tested. Pipes carrying superheated steam, the fire main, and pipes that are part of a fixed gas fire extinguishing system should always be tested. Some pipes might also be selected for dismantling and internal inspection. 4 Defense Acquisition University

5 Shielded Metal Arc Welding (SMAW), also known as Manual Metal Arc Welding (MMA or MMAW), flux shielded arc welding [1], or, informally, as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination. WELDING TERMS alloy alternating current amperage arc length arc voltage calcium carbon cast iron chipping hammer circuit conductor constant current consumable electrode cracking crater deoxidizer direct current electrode DEFINITIONS A metal consisting of a mixture of two or more materials. One of these materials must be a metal. Current that regularly reverses the direction of its flow. It is best to use AC for SMAW when welding larger workpieces with larger electrodes. The amount of current flowing in a circuit. SMAW uses amps. The distance from the electrode to the workpiece in an arc welding application. The amount of voltage present between the electrode and the workpiece. For SMAW, arc voltage ranges from volts. A nonmetallic material that is often present in the powdered coating of a SMAW electrode. Calcium floats to the top of the molten weld puddle and forms slag. A common, nonmetallic element found in all types of steel. Carbon is the main hardening element in steel. A metal consisting of iron, over 2.11% carbon, and 1-3% silicon. Cast irons normally contain trace amounts of other elements. The hammer used to scrape slag from a cooled weld bead. The chipping hammer is also sometimes called a scaling hammer. A controlled path in which electricity can flow. SMAW, like all arc welding processes, requires a closed circuit. A material that allows for the easy flow of electricity. The components in the SMAW circuit must be good conductors. Welding using a current that varies slightly with changes in voltage. SMAW applications use constant current welders. An electrode that conducts electricity to the arc but also melts into the weld as a filler metal. SMAW consumable electrodes also provide shielding that protects the arc and weld puddle. Cracks in the weld bead or base metal. Cracking can be the result of using excessive amperage with larger electrodes. A recess in the weld bead. A crater can cause cracking if it is not properly filled. A material that removes oxygen from the molten weld puddle and arc. Deoxidizers prevent oxygen from ruining a weld bead A current formed when electrons flow in one continuous direction. DC used during SMAW sometimes can cause arc blow. A device that conducts electricity to the welding circuit. SMAW electrodes conduct electricity, serve as the filler metal, and provide shielding for the arc and weld 5 Defense Acquisition University

6 WELDING TERMS electrode diameter electrode holder ferrous metal filler metal fillet joint flux gas metal arc welding gas shielding gas tungsten arc welding low-carbon steel manganese nonferrous metal porosity run-off tab shielding silicon slag spatter steel DEFINITIONS puddle. A measurement of the thickness of the electrode. Larger electrodes can improve productivity. The insulated handle that clamps onto the electrode. The welder holds this device during welding to control the arc A metal that contains iron. Steel is the most common ferrous metal. SMAW is most commonly used to weld ferrous metals A type of metal with similar properties to the base metal that is added to the SMAW weld. Filler metal often adds to the strength and mass of the welded joint. A type of weld that is triangular in shape and joins two surfaces at right angles to each other in a lap joint, T-joint, or corner joint. Fillet welds are the most common types of welds. A non-metallic material provided by the SMAW electrode, which protects the weld puddle and cooling metal from atmospheric contamination. An arc welding process in which the bare wire electrode and inert shielding gas are fed to the weld through a welding gun. It is also referred to as GMAW or MIG welding. A layer of inert or slightly reactive gas provided by the electrode. Shielding gas protects the weld puddle and arc from atmospheric contamination A very precise arc welding process that uses a nonconsumable tungsten electrode. It is also referred to as GTAW or TIG welding. Steel that contains less than 0.30% carbon. Low-carbon steel is also referred to as mild steel. A hard, brittle, gray-white metal that increases the hardenability of steel. Manganese also increases strength and hardness. A metal that does not contain iron. Aluminum and copper are common nonferrous metals. The trapping of hydrogen in a weld bead. Usually, porosity cannot be seen; however, excessive porosity can weaken a weld. A scrap piece of base metal with the same groove as the workpiece. Run-off tabs are tacked onto the end of the workpiece to allow the welder to extinguish the arc without forming a crater on the workpiece. A layer of inert or slightly reactive gas that protects the weld puddle and arc from atmospheric contamination. A nonmetallic material that is often present in the powdered coating of a SMAW electrode. Silicon acts as a deoxidizer. Cooled flux that forms on top of the bead. Slag protects cooling metal and is then chipped off. Liquid metal droplets expelled from the welding process. The amount of spatter that a SMAW process yields often depends on the electrode selected and welder skill. A metal consisting of iron and carbon, usually with small amounts of other 6 Defense Acquisition University

7 WELDING TERMS stick welding stringer bead tensile strength travel angle travel speed undercut voltage weave bead weldability work clamp DEFINITIONS elements. SMAW is often used to weld different types of steel Shielded metal arc welding. In industry, many welders refer to shielded metal arc welding as stick welding. A type of weld bead formed by moving the electrode straight across the joint. A good stringer bead looks like a roll of dimes. The ability of a metal to resist forces that attempt to pull apart or stretch it. The angle less than 90 degrees between the electrode and the weld. The speed at which the welder moves the electrode along the joint to make a weld. A gap left in a finished weld that should have been filled with weld metal. Undercut is unsightly but does not necessarily indicate a bad weld. The electrical force or pressure that causes current to flow in a circuit. SMAW uses volts. A weld bead formed by moving the electrode along the joint in a weaving motion. The ability of a material to be welded under imposed conditions into a specific, suitable structure and to perform satisfactorily for its intended use. The component that, along with the electrode, can come in direct contact with the workpiece during welding. The work clamp is connected to the welder with the work cable and provides ground for the SMAW circuit. 7 Defense Acquisition University