1、 METRIC MIL-STD-3021 w/CHANGE 1 13 July 2011_ SUPERSEDING MIL-STD-3021 4 August 2008 DEPARTMENT OF DEFENSE MANUFACTURING PROCESS STANDARD MATERIALS DEPOSITION, COLD SPRAY AMSC N/A AREA MFFP DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for Resal
2、eNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 ii FOREWORD 1. This standard is approved for use by all Departments and Agencies of the Department of Defense. 2. The purpose of this standard is to develop the manufacturing process controls for a cold spr
3、ay operation utilizing a high-velocity jet of solid-phase particles. The jet temperatures are below the melting thresholds of many engineering materials. This allows the process to be used to apply deposits on a wide variety of substrates, such as, alloys, ceramics, and plastics. Moreover, the delet
4、erious effects of deposit oxidation, evaporation, and residual thermal stresses are avoided. 3. This standard is required because the cold spray deposition process has significant differences from thermal spray coating technologies such as high velocity oxy-fuel (HVOF), detonation gun, plasma spray,
5、 flame spray, and arc spray. These process differences result in application criteria, process equipment, and operating parameters that are considerably different than previously documented processes. The objective is to enable the application of Cold Spray Deposition with the success of the aforeme
6、ntioned processes when properly applied. 4. Comments, suggestions, or questions on this document should be addressed to: Director, U.S. Army Research Laboratory, Material & Manufacturing Science Directorate, Materials Manufacturing Technologies Branch, Specifications and Standards Office, Attn: RDRL
7、-WMM-D, Aberdeen Proving Ground, MD 21005-5069 or emailed to richard.j.squillacioti.civmail.mil. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.daps.dla.mil/. Provided by IHSNot for ResaleNo repr
8、oduction or networking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 iii SUMMARY OF CHANGE 1 MODIFICATIONS The following modifications to MIL-STD-3021 have been made: Paragraph Modification 1.2 Added 1.2.1 Changed Figure 1 Changed Figure 2 Changed 3.1 Changed 3.4 Powder meter wheel.
9、 Deleted 4.1 Changed 4.3.1 Changed Table I Changed 4.3.2.2.2 Changed 4.3.3 Changed Figure 1 Changed 4.4 Changed 5.1.2 Changed 5.1.2.1 Changed 5.1.2.2.2 Changed 5.1.3.4 Changed 5.2.2 Changed Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-3021
10、 w/Change 1 iv CONTENTS PARAGRAPH PAGE FOREWORD ii 1. SCOPE 1.1 Purpose 1 1.2 Process. 1 1.2.1 Types. . 1 1.3 Applications. . 1 2. APPLICABLE DOCUMENTS 2.1 General 2 2.2 Government documents. 2 2.2.1 Specifications, standards, and handbooks. . 2 2.3 Non-Government publications 3 2.4 Order of precede
11、nce 3 3. DEFINITIONS 3.1 Cold spray. . 3 3.2 Nozzle. . 3 3.3 Powder lot. . 3 3.4 Simulated part. 4 3.5 Substrate 4 3.6 Lot 4 3.7 Pass. 4 3.8 Increment 4 3.9 Layer. 4 3.10 Thermal spraying. . 4 4. GENERAL REQUIREMENTS 4.1 Application 4 4.2 Process. . 4 4.2.1 Cold spray equipment 4 4.2.2 Material. 5 4
12、.2.2.1 Gas. . 5 4.2.2.1.1 Gas specifications 5 4.2.2.2 Coating powder. 5 4.3 Required procedures and operations. 5 4.3.1 Process control. . 5 4.3.1.1 Gauges, meters, and sensors 6 4.3.1.2 Checks 6 4.3.2 Surface preparation. 6 4.3.2.1 Cleaning. . 6 Provided by IHSNot for ResaleNo reproduction or netw
13、orking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 v CONTENTS PARAGRAPH PAGE 4.3.2.2 Handling and storage. 6 4.3.2.2.1 Handling. . 6 4.3.2.2.2 Storage. 6 4.3.2.3 Overspray protection. 6 4.3.3 Abrasive blast. . 8 4.3.3.1 Blast contamination 8 4.3.4 Preheating. . 8 4.3.5 Coating dep
14、osition. 8 4.3.6 Identification. . 8 4.4 Operator certification. 8 4.4.1 Cold spray operator. 8 4.4.1.1 Continuance of certification 9 5. DETAILED REQUIREMENTS 5.1 General. 9 5.1.1 Certification. 9 5.1.1.1 Certification samples. . 9 5.1.1.2 Re-certification . 9 5.1.2 Test specimens. 9 5.1.2.1 Metall
15、ographic test specimens . 9 5.1.2.1.1 Test specimen panel configuration 10 5.1.2.2 Bond strength test specimens. 10 5.1.2.2.1 Size. 10 5.1.2.2.2 Material. 10 5.1.2.2.3 Deposit. . 10 5.1.2.2.4 Deposition thickness. 10 5.1.3 Process approvals. . 10 5.1.3.1 Processing data. . 10 5.1.3.2 Sample part. .
16、10 5.1.3.3 Rework. . 10 5.1.3.3.1 Stripping. . 10 5.1.3.4 Metallographic test specimen. 10 5.1.4 Process certification. 11 5.2 Test methods. . 11 5.2.1 Visual. 11 5.2.2 Microscopic examination. 11 5.2.3 Oxides and porosity. 11 5.2.4 Bond strength test. 11 6. NOTES 6.1 Intended use 12 6.2 Acquisition
17、 requirements. 12 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 vi CONTENTS PARAGRAPH PAGE 6.3 Issue of DoDISS. . 13 6.4 Safety. 13 6.4.1 Material safety data sheets (MSDS). . 13 6.5 English units . 13 6.6 Subject term (key
18、word) listing. 13 TABLE I. Operating parameters . 6 FIGURE 1. High pressure powder injection system . 2 2. Low pressure powder injection system. 2 3. Typical cold spray control sheet 7 CONCLUDING MATERIAL 14 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IH
19、S-,-,-MIL-STD-3021 w/Change 1 1 1. SCOPE 1.1 Purpose. The procedures covered by this standard are intended to ensure that cold spray coating operations, either manual or automated, meet prescribed requirements. This process can be used to restore dimensionally discrepant parts, or parts requiring pr
20、otection from corrosion and wear (e.g. abrasion, cavitations, and erosion) but not limited to these applications. 1.2 Process. This standard describes the process requirements for surfacing by means of cold spray deposition. The term “cold spray” has been used to describe this process because both t
21、he temperature of the powder-laden gas jet and the temperature of the powder material are low enough to prevent a phase change or stress in the deposit or substrate. Cold spray is a process whereby metal powder particles are utilized to form a deposit by means of ballistic impingement upon a substra
22、te. The metal powders typically range in particle size from 1.0 to 100 micrometers (m) and are accelerated by injection into a high-velocity stream of gas. The high velocity gas stream is generated through the expansion of a pressurized, preheated, gas through a nozzle. The nozzle may be a contracti
23、ng-expanding supersonic type or a contracting sonic type. The pressurized gas is expanded in order to achieve high velocity, with an accompanying decrease in pressure and temperature. The powder particles, initially carried by a separate gas stream, are injected into the nozzle either at the nozzle
24、entrance (High Pressure Powder Injection) or at a lower pressure point downstream of the entrance (Low Pressure Powder Injection). The particles are then accelerated by the main nozzle gas flow and are impacted onto a substrate after exiting the nozzle. The solid particles that impact the substrate
25、above a threshold (critical) velocity for the powder and substrate combination will deform and bond in a dense layer. As the process continues, particles continue to impact the substrate and form bonds with the previously deposited material resulting in a uniform deposition with very little porosity
26、 and high bond strength. 1.2.1 Types. The two principal cold spray system configurations are depicted by Figures 1 and 2. The two configurations differ in the carrier gas, gas pressure, and powder injection location. Figure 1 shows a High Pressure Powder Injection System in which the main gas stream
27、 and the powder stream are both introduced into the inlet chamber of the nozzle. This configuration requires that the powder feeder be capable of high gas pressure. A low molecular weight gas, such as helium, is sometimes used as the accelerating gas when particles must be brought to very high veloc
28、ity. Figure 2 shows a Low Pressure Powder Injection System in which the powder stream is injected into the nozzle at a point where the gas has expanded to low pressure. This system generally utilizes readily available compressed air, but can utilize nitrogen and helium, as well. 1.3 Applications. Th
29、e superior qualities of cold sprayed deposits are often required by the application. For example, the high heat transfer coefficient and electrical conductivity of cold sprayed deposits favor its use in electronic applications. Applications for cold spray technology often occur in situations where c
30、onventional thermal metal spray technology cannot be successfully used and where cold spray will result in an improved deposit. These situations often occur when high temperatures cannot be tolerated by the substrate. Good corrosion protection is achieved by dense, impermeable cold sprayed deposits.
31、 Wear resistant, hard surfaces, such as MCrAlYs, can be deposited by cold spray when operated at its high-temperature end. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 2 High pressure gas0.25 5 MPaGas heaterPowder feederNoz
32、zleSubstrateFIGURE 1. High Pressure Powder Injection System. Gas heaterPowder feederLow pressure gas 0.1 0.5 MPaNozzleSubstrateHigh pressure gas0.5 1 MPaFIGURE 2. Low Pressure Powder Injection System. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections
33、 3, 4, or 5 of this standard. This section does not include documents cited in other sections of this standard or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all spec
34、ified requirements of documents cited in sections 3, 4, or 5 of this standard, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein.
35、 Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-S-5002 - Surface Treatments and Inorganic Coatings for Metal Surfaces of Weapons Systems (Copies of this document are available online at https:/assist
36、.daps.dla.mil/quicksearch/ or https:/assist.daps.dla.mil/ or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 3 2.3 No
37、n-Government publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. SAE INTERNATIONAL SAE-AMS 2750 - Pyrometry (Copies of this document are available
38、 from www.sae.org or SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001) ASTM INTERNATIONAL ASTM C633 - Standard Test Method for Adhesion or Cohesion Strength of Thermal Spray Coatings. ASTM E3 - Standard Guide for Preparation of Metallographic Specimens. ASTM E407 - Standard Pract
39、ice for Micro-Etching Metals and Aloys. (Copies of these documents are available from www.astm.org or ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.) 2.4 Order of precedence. In the event of a conflict between the text of this document and the references ci
40、ted herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. DEFINITIONS 3.1 Cold spray. Cold spray is a materials deposition process in which relatively small particles (rangin
41、g in size from approximately 1 to 100 micrometers (m) in diameter) in the solid state are accelerated to high velocities (typically 300 to 1200 meters/second), and subsequently develop a coating or deposit by impacting an appropriate substrate. Various termsincluding “kinetic energy metallization,”
42、“kinetic metallization,” “kinetic spraying,” “high-velocity powder deposition,” and “cold gas-dynamic spray method”have been used to refer to this technique. In most instances, deformable powder particles in a gas carrier are brought to high velocities through introduction into a nozzle, designed to
43、 accelerate the gas. The subsequent high-velocity impact of the particles onto the substrate disrupts the oxide films on the particle and substrate surfaces, pressing their atomic structures into intimate contact with one another under momentarily high interfacial pressures and temperatures. 3.2 Noz
44、zle. A gas manifold designed to accelerate a gas to high velocity. 3.3 Powder lot. A powder lot is all the powder of a specified type manufactured at the same time. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-3021 w/Change 1 4 3.4 Simulat
45、ed part. A simulated part is a test piece or section with a similar surface configuration to the part it represents. The simulated part will be approved by the acquisition authority. 3.5 Substrate. The material, work piece or substance on which a coating is deposited. 3.6 Lot. A lot is all the parts
46、 of a similar configuration, coated sequentially on the same machine setup using the same batch of coating material and process parameters, within a shift or eight hours of operation, and presented for processors inspection at one time. 3.7 Pass. A single traverse by the nozzle over the work piece. 3.8 Increment. The distance between adjacent passes (also called step size). 3.9 Layer. Multiple passes over the work piece that result in complete coverage. 3.10 Th
