Stainless Steel 17-7 PH is a precipitation-hardening stainless steel wire alloy containing approximately 16–18% chromium and 6.5–7.75% nickel, providing an exceptional combination of high strength, fatigue resistance, corrosion resistance, and formability. Through precipitation-hardening heat treatments, SS17-7 PH can achieve very high mechanical properties while maintaining good dimensional stability and spring performance. Stainless Steel 17-7 PH is commonly used for springs, retaining rings, aerospace components, diaphragms, wire forms, washers, fasteners, and other applications requiring excellent strength, elasticity, and long-term reliability under cyclic loading conditions.
17-7 PH stainless steel wire is identified under multiple naming conventions, including grade, alloy, and UNS designations; depending on the specification, industry, or standard being used.
Stainless steel 17-7 PH alloys are known by several names depending on the standard, specification, or drawing being used. Understanding these alternate names matters because the same alloy can appear under different designation systems across quotes, certifications, standards, and legacy prints. For buyers and engineers working with wire, this is especially important, since Stainless Steel 17-7 PH may be referenced through material standards tied to specific product forms and applications rather than by one simple trade name alone.
Type 17-7 PH is the traditional “Type” grade designation used throughout stainless steel specifications and industry practice and appears in technical descriptions, engineering standards, and material references for Stainless Steel 17-7 PH. Best for technical sales sheets, alloy descriptions, engineering drawings, and legacy documents where stainless steel grades are identified using the traditional Type system. Many engineers, buyers, and metallurgists still reference stainless grades in “Type” terminology, making this designation familiar, easy to recognize, and well aligned with longstanding industry documentation.
AISI 631 is the designation derived from the American Iron and Steel Institute (AISI) stainless steel grade classification system and is commonly used in engineering, aerospace, spring manufacturing, and industrial applications. Best for engineering discussions, procurement cross-references, technical specifications, and North American documentation that utilizes AISI terminology. The use of AISI 631 immediately identifies the material as the widely recognized precipitation-hardening stainless steel grade known commercially as 17-7 PH, making it useful for technical communication, material selection, and specification review across a wide range of high-strength and spring applications.
UNS S17700 is the official Unified Numbering System (UNS) designation for Stainless Steel 17-7 PH. Best for formal material identification, cross-referencing between industry standards, quality assurance documentation, mill certifications, engineering specifications, and multi-standard procurement requirements. This designation serves as the clearest and most unambiguous identifier when matching Stainless Steel 17-7 PH across different specification systems and international standards. It is especially useful when a drawing, certification, purchase order, or compliance document requires a formal material designation rather than a commercial or trade-style name.
Grade 631 is a generic technical descriptor commonly used in datasheets, engineering references, technical articles, and educational materials for Stainless Steel 17-7 PH. Best for technical overviews, material comparisons, specification discussions, and informational content. It reads naturally in explanatory writing and is particularly useful when comparing precipitation-hardening stainless steel grades, such as Grade 631 vs. Grade 630 or Grade 631 vs. Grade 15-5 PH. Because it uses straightforward technical language rather than a specific standards designation, Grade 631 is widely understood by engineers, buyers, students, and industry professionals across a broad range of aerospace, spring, and high-strength applications.
Precipitation Hardening Stainless Steel is a common technical description for Stainless Steel 17-7 PH because it achieves exceptionally high strength and hardness through a specialized precipitation-hardening heat-treatment process. Best for aerospace components, springs, retaining rings, diaphragms, washers, wire forms, and other high-performance applications requiring superior mechanical properties. This designation highlights the alloy’s unique ability to combine high strength, excellent fatigue resistance, corrosion resistance, and dimensional stability, making Stainless Steel 17-7 PH one of the most widely used precipitation-hardening stainless steel grades for spring and aerospace applications.
Semi-Austenitic Stainless Steel is a technical description commonly used for Stainless Steel 17-7 PH because it begins in an austenitic condition and can be transformed through heat treatment to achieve exceptionally high strength and hardness. Best for aerospace components, springs, diaphragms, retaining rings, wire forms, and other applications requiring a combination of formability and high mechanical performance. This designation highlights the alloy’s unique ability to be easily formed in its initial condition and then precipitation hardened to develop excellent strength, fatigue resistance, and dimensional stability.
Precipitation Hardening Semi-Austenitic Stainless Steel is a technical description commonly used for Stainless Steel 17-7 PH because it combines a semi-austenitic microstructure with precipitation-hardening heat treatment to achieve exceptionally high strength and fatigue resistance. Best for aerospace components, springs, diaphragms, retaining rings, washers, wire forms, and other demanding applications requiring both formability and high mechanical performance. This designation highlights the alloy’s unique ability to be formed in its softer condition and then heat treated to develop outstanding strength, hardness, dimensional stability, and long-term reliability under cyclic loading conditions.
Spring Grade Stainless Steel is a common industry description for Stainless Steel 17-7 PH because of its exceptional combination of high strength, fatigue resistance, elasticity, and dimensional stability. Best for springs, retaining rings, clips, washers, diaphragms, wire forms, and other components subjected to repeated loading and unloading cycles. This designation highlights the alloy’s ability to maintain excellent spring properties after precipitation-hardening heat treatment, making Stainless Steel 17-7 PH one of the most widely used stainless steel grades for demanding spring and elastic component applications.
High Strength Spring Stainless Steel is a common technical description for Stainless Steel 17-7 PH because of its ability to achieve exceptionally high strength, fatigue resistance, and elastic recovery through precipitation-hardening heat treatments. Best for springs, retaining rings, clips, diaphragms, washers, wire forms, and other high-performance components subjected to repeated stress and cyclic loading. This designation highlights the alloy’s outstanding spring properties and its ability to maintain strength, dimensional stability, and long-term reliability in demanding aerospace, industrial, and mechanical applications.
Aerospace Spring Stainless Steel is a common industry description for Stainless Steel 17-7 PH because of its exceptional combination of high strength, fatigue resistance, corrosion resistance, and dimensional stability. Best for aerospace springs, retaining rings, diaphragms, clips, actuators, wire forms, and other critical aircraft and aerospace components. This designation highlights the alloy’s ability to maintain reliable spring performance and mechanical integrity under demanding operating conditions, making Stainless Steel 17-7 PH one of the most widely used stainless steel grades for aerospace spring and precision-engineered applications.
ASTM 631 is a common reference to Stainless Steel 17-7 PH when specified under ASTM material standards. Best for engineering specifications, procurement documents, quality requirements, and manufacturing applications that follow ASTM standards. The designation ASTM 631 helps identify the alloy within ASTM-controlled specifications and is frequently used in technical documentation, certifications, and material purchasing requirements, particularly where high strength, fatigue resistance, corrosion resistance, and precipitation-hardening stainless steel performance are required.
Chromium-Nickel-Aluminum Precipitation Hardening Stainless Steel is a broad technical description used to classify Stainless Steel 17-7 PH based on its alloy chemistry and strengthening mechanism. Best for educational content, metallurgy discussions, and technical overviews of precipitation-hardening stainless steel families. This designation highlights the alloy’s chromium and nickel content for corrosion resistance, along with aluminum, which contributes to the precipitation-hardening process that develops exceptionally high strength, fatigue resistance, and spring performance. It identifies Stainless Steel 17-7 PH as a high-strength precipitation-hardening alloy widely used in aerospace, spring, and precision-engineered applications.
Stainless steel wire alloys are used in various industries, including:
Sunset Wire can manufacture custom diameters of SS17-7PH for your project. Common sizes of Type 17-7 PH include:
Sunset Wire stocks a large inventory of stainless steel wire to ensure you get it fast. Get your wire in 1 lb cans, 1 lb spools or 5 lb spools. Other spool sizes are available upon request.
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Sunset Wire provides domestically drawn wire in various diameters, lengths and packages. Get your stainless steel wire delivered anywhere in the US thanks to our large inventory and dedicated supply chain management capabilities.