PLATING QUESTION |
| 03-06 11:05:32 来源： 作者： |
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PLATING QUESTION Inquiry (采购产品): PLATING QUESTION Hello, Please advise if you can plate to the attached requirements and supply full plating cert , which would also state thickness of the plating. M/C 0236 Description: ALLOY STEEL; UNS G41400 (4140), UNS G40370 (4037), UNS H86400 (8640H) FOR CAP SCREWS, BOLTS, AND SET SCREWS. 0.0005 INCH NOMINAL THICK ZINC PLATE, TRIVALENT CHROMATE PASSIVATION WITH SEALER PER JOHN CRANE STANDARD AE-2-2510. COLOR IS (BLUISH) SILVER. PROCESS TO PRODUCE A FINISH CAPABLE OF EXCEEDING 200 HOURS OF NEUTRAL SALT SPRAY TO WHITE CORROSION PRODUCTS If you can, can we send you samples for plating for our customer to test ? Please advise thank you Pauline Key Words: 1.0 PURPOSE To document the requirements of electrodeposited zinc coated fasteners and subsequent processes. 2.0 SCOPE To establish uniform practices for vendors and acceptance criteria for plated fasteners. 3.0 STANDARD 3.1 Before plating the fasteners shall meet the following criteria: 3.1.1 Inch cap screws less than or equal to 1 inch in size shall meet the requirements of Class 3A threads. 3.1.2 Inch cap screws larger than 1 inch in size shall meet the requirements of Class 2A threads. 3.1.3 Inch set screws shall meet the requirements of Class 3A threads. 3.1.4 Metric cap screws and set screws shall meet the requirements of Class 4g6g threads. 3.1.5 Inch and metric socket head fasteners shall accept standard hex keys for the size specified. 3.2 After plating it is possible that the external threads of cap screws and set screws will not pass inspection using standard gages as the external thread classes noted above do not include an allowance for plating. According to the Unified Screw Thread standards, in a worse case scenario, the Maximum Major Diameter and Maximum Pitch Diameter for a Class 3A external thread is the same as the Minimum Major Diameter and the Minimum Pitch Diameter for a Class 2B internal thread respectively. Historically, plated external threads have not had a fit tolerance problem with their respective component internal threads. Inspection of plated fasteners shall be conducted as follows: 3.2.1 First level of inspection shall be with standard thread gages for the noted thread class. 3.2.2 If the fastener does not pass the inspection per 3.2.1 then inspection should utilize a stocked component using the applicable internal threads. Alternately, a set of John Crane manufactured gages can be made for incoming inspection. 3.2.3 Failure to pass 3.2.2 will require sorting or discarding of the lot depending upon the size of the order. 3.3 Approved zinc plating/trivalent chromate/sealer processes: 3.3.1 0.0005 inch nominal thick zinc plating, MacDermid Clepo Chromax ELV Trivalent Chromate with MacDermid Ultraseal sealer. 3.3.2 0.0005 inch nominal thick zinc plating, Accu-Labs 622 Trivalent Blue Trivalent Chromate with New Surface Technologies Techniseal RP 90A sealer. 3.4 Hardness, Tensile Strength, and Baking Requirements: 3.4.1 The hardness of the fastener is specified according to the applicable standard in 3.5. 3.4.2 According to ASTM B633, all electroplated parts having a tensile strength of 1200 MPa (174,045 psi) or higher (38 HRC or higher) shall be baked at a minimum of 190oC (375oF) for 3 hours or more within 4 hours after electroplating to provide hydrogen embrittlement relief. 3.5 Applicable ASTM Standards (per type of fastener) 3.5.1 ASTM A574/574M Alloy Steel Socket-Head Cap Screws (inch/metric) 3.5.2 ASTM F912/912M Alloy Steel Socket Set Screws (inch/metric) 3.5.3 ASTM F835/835M Alloy Steel Socket Button and Flat Countersunk Head Cap Screws (inch/metric) 3.5.4 ASTM A354 Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners 3.5.5 ASTM F568 Carbon and Alloy Steel Externally Threaded Metric Fasteners 3.5.6 ASTM B633 Electrodeposited Coatings of Zinc on Iron and Steel 3.6 The alloy steel parts as coated shall not have any visible rust or corrosion visible on any external or internal surfaces. 4.0 NOTES Original issue “A” effective 12/20/2006. “B” Added sections 3.2 & 3.3 effective 3/20/2007. **** Hidden Message ***** PAULINE FIRKINS NAPERVILLE, IL 60563 USA Company: GE SUPPLY LOGISTICS Title: INSIDE SALES Fax: 630-718-6910 E-mail: pauline.firkins@ge.com **** Hidden Message ***** pauline.firkins@ge.com |
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