Chrome Vanadium Springs
These steels work best on heat treatment and possess high strength, toughness, and resistance to wear and fatigue.
Vanadium particularly improves high temperature hydrogen cracking of steel and chrome and molybdenum provide high strength even at higher temperature.
| Technical Specification | Chrome Vanadium |
|---|---|
| Nominal Composition |
C: 0.48 - 0.53 Cr: 0.80 – 1.10 V: 0.15 |
| Density |
0.284 lb./in3 |
| Modulus of Elasticity (E) |
30 x 106 psi |
| Modulus of Rigidity (G) |
11.6 x 106 ksi |
| Coefficient of Expansion |
--- |
| Electrical Resistivity |
32.3 µΩ.in |
| Thermal Conductivity |
108 Btu/(hr/ft2/in/°F) |
| Min Size |
0.026 in (0.500 mm) |
| Max Temp |
220oC (425oF) |
| Uses |
Chrome-vanadium steel with medium high carbon content (SAE 6150) is used to make springs |
Custom Chrome Vanadium Steel Springs FAQs
What is chrome vanadium spring steel?
Chrome vanadium is a medium high carbon low alloy spring steel. The published composition is 0.48 to 0.53 percent carbon, 0.80 to 1.10 percent chromium, and 0.15 percent vanadium, and the grade is identified as SAE 6150. Chromium raises hardenability and strength. Vanadium forms fine carbides that refine grain structure, improve resistance to high temperature hydrogen cracking, and help the material hold strength as temperature rises. The alloy responds well to heat treatment and comes out with high strength plus good wear and fatigue resistance, which is why it is a standard pick for dynamically loaded springs.
What is chrome vanadium used for in spring work?
The published use for the grade is spring making, and in practice chrome vanadium goes into high stress dynamic service: engine valve springs, high stressed suspension springs on higher performance vehicles, and components that see repeated shock loading. CTI's carbon alloy documentation groups it with chrome silicon as the two low alloy grades suited to higher temperature service and repeated shock, purchased against ASTM A231 and ASTM A232 for chrome vanadium. CTI stocks pre-tempered chrome vanadium in those specifications, and material in that condition typically requires only tempering after coiling.
What is the maximum service temperature for a chrome vanadium spring?
The specification table lists 220 degrees C (425 degrees F). That is more than double the 200 degrees F published for plain carbon 1050, and it is the main technical reason to pay for the alloy. Chromium and vanadium both help the material resist softening at temperature. Above 425 degrees F, expect load loss from relaxation well before any fracture, so a spring holding a calibrated force needs either derating or a move into a different material class. Stainless and nickel alloys cover the ranges above what chrome vanadium supports.
What is the smallest chrome vanadium wire size available?
The minimum size row lists 0.026 in (0.500 mm). Chrome vanadium is available as pre-tempered wire in the smaller diameters and as hot rolled bar in the heavy sections, and which form you receive changes the process route entirely. Pre-tempered wire is cold coiled and then tempered or stress relieved. Hot rolled bar is formed and then fully quenched and tempered. State the diameter and whether pre-tempered material is acceptable when you send the RFQ, since that decision affects both achievable tensile strength and the dimensional control CTI can hold.
How does chrome vanadium compare with chrome silicon?
Both are low alloy spring steels for high stress dynamic work, both are normally bought pre-tempered, and both outperform hard drawn or oil tempered carbon wire on fatigue life and temperature capability. Chrome silicon, specified as ASTM A401, generally reaches higher tensile strength and tolerates somewhat higher temperature, making it the choice for the most highly stressed valve and suspension springs. Chrome vanadium, ASTM A231 and A232, gives better toughness and shock resistance at slightly lower strength. CTI stocks both, plus ASTM A1000 and ASTM A877, so the grade follows the requirement rather than availability.
Does a chrome vanadium spring need stress relief after coiling?
Pre-tempered chrome vanadium wire is cold coiled and then tempered, or stress relieved, to remove the residual tensile stress that coiling leaves on the outer wire surface. Skipping that step produces a spring that takes excessive set on first loading and gives up fatigue life. Hot rolled bar sections need the full quench and temper cycle instead. Dynamically loaded parts should also be shot peened after thermal processing to put the surface into compression. Coiling Technologies performs heat treating and shot peen in house, keeping both operations inside the same quality system.
Is corrosion protection required on chrome vanadium springs?
Yes. One percent chromium does not passivate, so chrome vanadium rusts in humid, outdoor, or washdown conditions and needs a coating or a conversion process. Powder coating is available in house at CTI. Electroplating deserves specific caution with this material, because pre-tempered chrome vanadium runs at high hardness, and high hardness pre-tempered wire is the most susceptible to hydrogen embrittlement during plating. Where plating cannot be avoided, bake promptly after plating and consider a lower hardness grade. Where the environment is the real constraint, move to stainless or a nickel alloy.
What test data can CTI provide on a chrome vanadium spring order?
Available documentation includes material certifications with chemistry and mechanical property data, dimensional inspection reports listing measured values against drawing tolerances, first article inspection paperwork, load test data, and traceability from the finished spring back to incoming raw material. On a dynamically loaded chrome vanadium part, the material certification and the load test data carry the most weight, since the fatigue performance you are paying for depends on tensile strength and surface condition being correct. CTI is ISO 9001:2015 certified and audited regularly, with products analyzed before and during production against the customer specification.
