Comparison of Cleaning Methods for Various Materials of Auto Repair Hardware Tools

1. Carbon steel
· Composition: Iron + Carbon, with no or extremely trace amounts of alloying elements
· Advantages: Lowest cost, easy to process
· Disadvantages: Hardness and toughness cannot be achieved simultaneously; hard and brittle or soft and tough; poor rust resistance
· Applications: Home DIY, disposable tools, low-end wholesale by weight
· Identification: The surface is usually blackened, and chrome plating is also prone to rusting

2. Chromium-vanadium steel (Cr-V)
· Composition: Added chromium (Cr) to enhance hardness and rust resistance, and vanadium (V) to refine grain structure and improve toughness.
· Advantages: Offers the best cost-performance ratio, balanced overall performance, and is the most mainstream in the tool industry.
· Disadvantages: Has lower impact resistance than Cr-Mo and may break when used in impact wrenches.
· Applications: Commonly used in auto repair shops, sockets, wrenches, and extension rods.
· Identification: Surface chrome-plated, often marked with “Cr-V” or “Chrome Vanadium”.

3. Chromium-molybdenum steel (Cr-Mo)
· Composition: Added chromium (Cr) and molybdenum (Mo), molybdenum can enhance high-temperature strength and impact resistance.
· Advantages: Excellent toughness, good impact resistance, deforms before breaking under high torque (high safety).
· Disadvantages: Cost is higher than Cr-V, hardness is slightly lower than S2.
· Applications: Pneumatic impact wrench sockets, heavy-duty tools, industrial-grade scenarios.
· Identification: The surface is often treated with matte or black electrophoresis, and marked with “Cr-Mo” or “Chrome Molybdenum”.

4. S2 steel
· Composition: Silicon (Si) enhances the elastic limit, molybdenum (Mo) + vanadium (V) refines the grain structure, and has a high carbon content.
· Advantages: Highest hardness (HRC 58±), excellent wear resistance, and strong torque capacity.
· Disadvantages: Highest cost, and slightly lower toughness than Cr-Mo (too hard and brittle).
· Applications: Screwdriver bits, Allen wrenches, and high-torque small-sized tools.
· Identification: The surface is often sandblasted or matte-finished, and marked with “S2” or “S2 Steel”.