1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2013 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J1781_201305 SURFACE VEHICLE RECOMMENDED PRACTICE J1781 MAY2013 Issued 1982-12 Re
5、affirmed 2013-05 Superseding J1781 NOV2006 Ship Systems and Equipment Materials for Fluid Systems RATIONALE J1781 has been reaffirmed to comply with the SAE five-year review policy. TABLE OF CONTENTS 1. Scope 1 1.1 Purpose . 1 2. References 2 3. Marine Environment 3 4. Corrosion . 4 5. Design Guidel
6、ines for Metals 10 6. Non-Metallics . 12 7. Applications . 13 8. Conclusions . 15 9. Notes . 16 1. SCOPE The scope of this Recommended Practice is to delineate groups of materials for which there is considerable fabrication and operating experience in the sea water environment. In addition, some of
7、the more promising materials for possible future applications are covered. 1.1 Purpose The purpose of this Recommended Practice is to define materials for use in fluid systems of marine vehicles, including submersibles and advanced surface craft. This report is more particularly directed to the desi
8、gner of fluid power and piping systems on board marine vehicles. SAE J1781 Reaffirmed MAY2013 Page 2 of 16 2. REFERENCES 2.1 Applicable Publications The following publications form a part of the specification to the extent specified herein. The latest issue of the documents shall be used except in t
9、hose cases where an invitation for bid or procurement contract specifically identifies the issues in effect on a particular date. 2.1.1 SAE Publications Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www
10、.sae.org. SAE AMS 2447 Coating, Thermal Spray High Velocity Oxygen/Fuel Process SAE J1777 General Environmental Considerations for Marine Vehicles SAE J1778 Ship Systems and Equipmentg127Recommended Practice for Hydraulic Fluid Selection SAE J1779 Ship Systems and EquipmentHydraulic System Design Cr
11、iteria for Marine Vehicles SAE J2280 Ship Systems and Equipmentg127Fastenersg127Selection and Identification Requirements 2.1.2 Department of Defense Publications Available from U.S. Government, DODSSP, Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-509
12、4, Tel: 215-697-2179, http:/assist.daps.dla.mil/quicksearch/. MIL-B-24480 Bronze, Nickel-Aluminum (UNS C95800) Castings for Seawater Service MIL-STD-438 Schedule of Piping, Valves, Fittings and Associated Piping Components for Submarine Service MIL-STD-777 Schedule of Piping, Valves, Fittings and As
13、sociated Piping Components for Naval Surface Ships 2.1.3 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM B 150/B 150M Aluminum Bronze Rod, Bar and Shapes ASTM B 677 Standard Specification for UNS N089
14、25, UNS N08354, AND UNS N08926 Seamless Pipe and Tube ASTM G 82 Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion Performance SAE J1781 Reaffirmed MAY2013 Page 3 of 16 2.2 Related Publications The following publications are provided for information purpose
15、s only and are not a required part of this document. 2.2.1 Industry Reports DTIC No. ADA055609Materials Study for High Pressure Sea Water Hydraulic Tool Motors; Mechanical Technology Inc., Latham, NY, April 1, 1978, available from DTIC (see 2.2.3) Fink, F.W. and the area where reduction is occurring
16、, a cathode. A corrosion cell, then consists of four elements: 1. Anode, seat of corrosion (oxidation) 2. Cathode, seat of reduction 3. Metallic path for electrons from anode to cathode 4. Electrolytic path of current from anode to cathode The following means may be employed for reducing corrosion r
17、ate: (a) isolate the anode from the cathode electrically along the metallic path; (b) isolate the surface of the cathode with nonconductive coating; (c) increase the resistance of the electrolytic path by means of nonconducting piping; (d) connect the anode to a sacrificial anode at a still lower po
18、tential; (e) impress a protective current from an external source flowing in the electrolyte to the anode. Cathodic protection requires metallic and electrolytic conduction paths to all parts to be protected. SAE J1781 Reaffirmed MAY2013 Page 7 of 16 TABLE 4 - GALVANIC SERIES IN SEA WATER(1)Material
19、 Volts (Calomel Reference) Max. Volts (Calomel Reference) Min. Graphite Cathodic +.30 +.20 Platinum g110 +.25 +.19 Ni-Cr-Mo Alloy C +.09 .04 Titanium +.07 .05 Ni-Cr-Mo-Cu-Si Alloy B +.05 +.02 Ni-Fe-Cr Alloy 825 +.05 .02 Alloy 20 Stainless Steels +.06 .04 316, 317 Stainless Steels, Passive +.00 .10 N
20、i-Cu Alloys 400, K-500 .03 .13 302, 304, 321, 347 Stainless Steels, Passive .05 .10 Silver .10 .15 Nickel 200 .10 .20 Silver Braze Alloys .10 .20 Ni-Cr Alloy 600 .14 .18 Ni-Al Bronze .15 .22 70-30 Copper Nickel .18 .24 Lead .19 .25 430 Stainless Steel, Passive .20 .27 80-20 Copper-Nickel .21 .27 90-
21、10 Copper-Nickel .22 .28 Nickel Silver .25 .28 410, 416 Stainless Steels, Passive .25 .35 Tin Bronzes (G actually superior in stagnant water. Use MIL-B-24480 and ASTM B150 Alloy C-63200 for wrought material Including propellers. Wide use as non-ferrous spring materials. SAE J1781 Reaffirmed MAY2013
22、Page 12 of 16 TABLE 5 - CORROSION BEHAVIOR OF COMMON ALLOYS IN SEA WATER (CONTINUED) Alloy Type UNS No. Alloy Designation Corrosion Resistance Remarks(2)Aluminum A95083 A95086 A96061 A03560 A97xxx A92xxx 5000 Series 6061-T6 Alloy 356 7000 Series 2000 Series Good Fair-Good Fair-Good Very Poor Very Po
23、or 5086 is best. 5083 also good. Must be isolated from steel or other cathodic metals. Condensation drip from copper alloys may cause severe pitting even though the aluminum is electrically isolated. Same remarks as above. Responds well to cathodic protection. Same remarks as above. It is the prefer
24、red casting alloy. Do not use for new design. Encapsulate component with paint and seal, provide cathodic protection. Do not use. Magnesium Very Poor Do not use. 1. Trade Name. 2. For more detailed information on materials, their availability and test reports it is recommended that the web be search
25、ed by alloy designation and UNS number. 6. NON-METALLICS Non-metallics cover a wide variety of materials including thermoplastics, composites, glass, elastomers and coatings. 6.1 Plastics The term “plastics” covers a variety of organic materials ranging from soft to high strength. The number of plas
26、tic materials and their usage for view ports, buoyancy material, gaskets, packings, housings flexible hose and cable expanded at an accelerating rate in the 1970s and 1980s. Delrin1, epoxies, fluorocarbons, polyamids (Nylon1), and phenolics are listed to name a few. The strength characteristics and
27、other properties of plastics are specific to the type of resin, additives and curing used. Technical data may be obtained from manufacturers literature, handbooks, and a multitude of reports generated from Government sponsored programs in various technical areas. 6.2 Composites Fiber reinforced plas
28、tics provide strength characteristics in the direction of fibers equal to or better than metal. Transverse strength, shear strength and bearing strength, however, are no better than that of the matrix, and allowance must be made for in the design of mechanical or adhesive bonded joints. Water seepag
29、e at the ends of the fibers must be eliminated or the structural system may be destroyed. Glass reinforced plastics (GRP) gained wide acceptance in the 1970s for secondary structures, such as fairings, sea water tanks and piping, because of low cost and corrosion resistance. Impact strength in compr
30、ession and fatigue life are poor. Advanced composites such as carbon fiber reinforced plastics have been developed which exceed metals in mechanical properties including strength and stiffness in the direction of the fibers. Graphite-fiber reinforced Teflon1is cathodic when coupled to most metal all
31、oys, and may accelerate their corrosion over the contact area. Torlon 4275 is an example of a composite with a combination of ingredients for achieving desired results. It is a polyamide-imide with glass-fiber reinforcing and a Teflon1filler for lubrication. Torlon has relatively low swell and is us
32、ed for vanes in a sea water motor. Vespel1is another example: it is used as a hydraulic motor spline adapter to eliminate fretting. 1Trade Name. SAE J1781 Reaffirmed MAY2013 Page 13 of 16 6.3 Elastomeric Materials Elastomeric materials are particularly suited for use in applications as insulation, d
33、iaphragms, coatings, shells, pottings, shock absorbers, gaskets, O-rings, bladders, storage bags and hose, and reinforcing gas flasks. Elastomeric compounds that can be readily obtained are nitrile, neoprene, butyl, natural rubber, silicone, polyacrylic and polysulfide rubbers, polyethylene, fluorin
34、ated butyl acrylate and fluorocarbon (Viton2) rubbers. The list is being lengthened by the addition of tetrafluoroethylene (Teflon2), polypropylene, polyamids and others, plus their composites, and high strength aramid filaments such as KEVLAR2. KEVLAR is used increasingly in lieu of glass fibers in
35、 dry applications. 6.3.1 Seals and Gaskets In piping systems, one of the major uses of elastomeric materials is for O-rings and other seal configurations. The elastomeric material selected must be compatible with the fluid used in the system and the pressure to which it will be subjected. The number
36、 of seal materials used should be minimized to reduce logistic support requirements and to minimize the possibility of installing the wrong seal material. Fluorocarbon rubber is one seal material that is compatible with almost all ship fluid systems. SAE J1778 indicates the compatibility of various
37、seal materials with various ship hydraulic fluids and seawater. 6.4 Protective Coatings In shallow water, coatings are needed against marine growth. At depths of about 1200 to 1800 m (4000 to 6000 feet) and deeper, there is very little fouling; hence, in such applications there is a need to cope onl
38、y with corrosion. Protection of metallic surfaces through the use of coatings consists of covering them with non-metallic materials that are more resistant to the elements of destruction than the underlying metal itself. Tufram2and Nituff2finishes applied to aluminum alloys provide sealing of porosi
39、ties and solid film Teflon2lubrication. Coating of the anodic metal of a galvanic couple is counterproductive. Flaws in Nituff2coating of A-356 aluminum seawater valves installed with titanium fittings have perforated in a few months. Tiodize2and Candizing2, provide a hard surface for titanium and m
40、inimize galling. 6.5 Ceramics and Ceramic Coatings A new generation of high strength ceramics has become commercially available in solid, bonded powder or flame sprayed coating form. These include, but are not limited to aluminum, chromium, titanium and zirconium oxides, silicon and tungsten carbide
41、 and silicon nitride. Compressive strengths are in excess of 2100 MPa (300 000 psi) with flexural strength in the 300 to 600 MPa (44 000 to 87 000 psi) range reported. Specific gravities range from 3.2 to 3.8 for non-porous solids. Ceramics resist heat, corrosion, and wear, but their ductility is ni
42、l and impact resistance is poor. The following rules may be applied for structural design: a. Minimize or avoid stress concentrations arising from changes in component cross section. Use large radii. b. Reduce contact stress of mating parts by promoting good fits using close tolerances and fine fini
43、shes. c. Avoid unnecessary tensile stress. d. Exercise care in the assembly of parts to avoid scratching or chipping of the surfaces. Provide a means to prevent surface damage during service. 7. APPLICATIONS The following examples show past and present practice in fluid power system design. 2Trade N
44、ame. SAE J1781 Reaffirmed MAY2013 Page 14 of 16 7.1 Hydraulic Tubing3Hydraulic lines have been made of 304 stainless steel, 316L and 21-6-9 on advanced marine craft. Pitting and stress corrosion were encountered in areas exposed to salt spray in tropical climates where hydraulic fluid temperatures e
45、xceeded 120 F, and coating was required. In cold climates, 21-6-9 (Nitronic440) has been adequate. Aluminum tubing used in the 1960s was not adequate. Aluminum alloy 6061-T6 is used for vent lines. Titanium has excellent corrosion resistance and is light weight. The alloy Ti-3AI-2.5V has high streng
46、th to weight ratio and sufficient ductility for tube fabrication. It is a promising candidate for future surface craft. 7.2 Hydraulic Valves3Navy has used titanium alloy 6AI-4V, copper nickel and Nitronic450 (ARMCO) for valves. On hydrofoils, 6061-T6 valve housings are used in protected locations. 7
47、.3 Hydraulic Actuators and Linkages3Hydraulic actuators of hydrofoils are 17-4PH stainless steel. Low alloy carbon steels were not adequate in locations exposed to spray or splash. Titanium actuators may be considered for fully submerged installations to minimize the need for actuator linkages. Link
48、ages are typically Ti-6AI-4V, Inconel 625, or cathodically protected 17-4PH. Actuator and bell crank bearings are generally self-aligning, self-lubricating type. Outer race liners are either tetrafluoroethylene fabric or an injection molded plastic which are galvanically isolating. Balls are 6AI-4V
49、titanium alloy with wear resistant chromium oxide ceramic coating. 17-4PH balls had crevice corrosion. Chromium plated piston rods have been successful in air and splash zones, but not in fully submerged applications where chromium corrodes. Bronze scraper rings have caused electrolytic attack on chromium plating, which can be avoided by non-metallic Teflon
