What is a stainless steel lead screw?

The raw material for stainless steel lead screws is typically quenched and tempered carbon steel. While alloy steels offer greater reliability, they come at a higher cost. In China, 45# steel subjected to quenching and tempering, or 40Cr, is commonly used as the preferred choice. Some manufacturers also employ stainless steels—such as grades 200, 201, 303, 304, and 316—particularly for fine‑pitch multi‑start lead screws.

The raw material for stainless steel lead screws is typically quenched-and-tempered steel. While alloy steels are comparatively more reliable, they come at a higher cost. In China, 45# steel subjected to quenching and tempering, or 40Cr, is commonly the preferred choice. Some also use stainless steels—such as 200, 201, 303, 304, and 316—particularly for fine‑pitch multi‑start lead screws.

Materials: (1) Rolled ball screw: The screw shaft is made of S55C (equivalent to China’s Grade 55 steel), with high-frequency quenching to a hardness of 56–62 HRC; the nut is made of SCM420 (equivalent to 20CrMo), case-carburized and quenched to a hardness of 58–62 HRC.

(2) Precision ball screws: The screw shaft is made of SCM415 (equivalent to 15CrMo), case-hardened and quenched to a hardness of 58–62 HRC; the nut is made of SCM420 (equivalent to 20CrMo), case-hardened and quenched to a hardness of 58–62 HRC.

 

Specifically: Japan: THK ball screws, KSS ball screws, NSK ball screws, TOSOK ball screws, MISUMI ball screws, KURODA ball screws, and more. Taiwan: HIWIN ball screws, TBI ball screws, PMI ball screws, CPC ball screws, ABBA ball screws, GTEN ball screws, and others. Germany: HIPP miniature ball screws, LAIEN ball screws, REXROTH ball screws, BLIS ball screws, and more.

[Stainless Steel]

The corrosion resistance of stainless steel decreases as carbon content increases; therefore, most stainless steels have low carbon levels, with a maximum not exceeding 1.2%, and some steels even have a carbon content (Wc) below 0.03% (e.g., 00Cr12). The primary alloying element in stainless steel is chromium (Cr); only when the Cr content reaches a certain threshold does the steel exhibit corrosion resistance. Consequently, stainless steels typically contain at least 10.5% chromium. Additionally, stainless steels often contain other alloying elements such as nickel (Ni), titanium (Ti), manganese (Mn), nitrogen (N), niobium (Nb), molybdenum (Mo), silicon (Si), and copper (Cu).

Stainless steels are commonly classified according to their microstructural characteristics as follows: 1. Austenitic–ferritic (duplex) stainless steel; 2. Ferritic steel; 3. Austenitic steel; 4. Precipitation‑hardening stainless steel; and 5. Martensitic steel, among others. Additionally, they can be categorized by composition into chromium stainless steel, chromium–nickel stainless steel, and chromium–manganese–nitrogen stainless steel, among others.

1. Austenitic–ferritic (duplex) stainless steel: Combines the advantages of both austenitic and ferritic stainless steels and exhibits superplasticity. It is a stainless steel in which the austenitic and ferritic phases each account for approximately half of the microstructure. With relatively low carbon content, it typically contains 18%–28% chromium and 3%–10% nickel. Some grades also incorporate alloying elements such as molybdenum, copper, silicon, niobium, titanium, and nitrogen. This class of steel integrates the characteristics of both austenitic and ferritic stainless steels; compared with ferritic steels, it offers higher ductility and toughness, no room‑temperature brittleness, and significantly improved resistance to intergranular corrosion and weldability. At the same time, it retains certain features of ferritic stainless steels, including 475°C embrittlement and high thermal conductivity, as well as superplasticity. Compared with austenitic stainless steels, it provides higher strength and markedly superior resistance to intergranular corrosion and chloride‑induced stress corrosion. Duplex stainless steels also demonstrate excellent pitting resistance and are a type of nickel‑saving stainless steel.

2. Ferritic stainless steels: Contain 12% to 30% chromium. Their corrosion resistance, toughness, and weldability improve with increasing chromium content, and they exhibit superior resistance to chloride‑induced stress corrosion compared with other types of stainless steel. Examples include Crl7, Cr17Mo2Ti, Cr25, Cr25Mo3Ti, and Cr28. Due to their high chromium content, ferritic stainless steels offer excellent corrosion and oxidation resistance; however, their mechanical properties and formability are relatively poor. They are typically used in acid‑resistant structures subjected to low stresses or as oxidation‑resistant steels. These steels resist corrosion by atmospheric conditions, nitric acid, and saline solutions, and they also feature good high‑temperature oxidation resistance and a low coefficient of thermal expansion. Consequently, they are employed in equipment for nitric acid and food processing plants, and can be fabricated into components operating at elevated temperatures, such as gas‑turbine parts.

3. Austenitic stainless steels: Contain more than 18% chromium, along with approximately 8% nickel and small amounts of molybdenum, titanium, nitrogen, and other elements. They exhibit excellent overall performance and are resistant to corrosion by a wide range of media. Common grades include 1Cr18Ni9 and 0Cr19Ni9. In 0Cr19Ni9 steel, the carbon content (Wc) is less than 0.08%, indicated by the “0” in the grade designation. These steels contain substantial amounts of Ni and Cr, ensuring an austenitic microstructure at room temperature. They offer good ductility, toughness, weldability, and corrosion resistance, as well as being non-magnetic. They demonstrate superior corrosion resistance in both oxidizing and reducing environments and are used to fabricate acid‑resistant equipment, such as corrosion‑resistant vessels and linings, transport pipelines, and components for nitric‑acid‑resistant apparatuses. Additionally, they can serve as the primary material for stainless‑steel watch cases and decorative items. Austenitic stainless steels are typically subjected to solution treatment: the steel is heated to 1050–1150°C and then quenched in water or air to obtain a single‑phase austenitic microstructure.

4. Precipitation‑hardening stainless steel: With an austenitic or martensitic microstructure, common grades include 04Cr13Ni8Mo2Al. This type of stainless steel can be strengthened—i.e., hardened—through precipitation hardening (also known as age hardening).

5. Martensitic stainless steels: These steels exhibit high strength but relatively poor ductility and weldability. Common grades include 1Cr13 and 3Cr13. Due to their higher carbon content, they possess superior strength, hardness, and wear resistance, though their corrosion resistance is somewhat inferior. They are used for components that demand both high mechanical performance and moderate corrosion resistance, such as springs, turbine blades, and hydraulic press valves. These steels are typically employed after quenching and tempering treatments.