Carbon & Alloy Steel Machined Parts — 1045, 1215, 4140

Grades we machine

We machine steel machined parts from three grades that cover most carbon and alloy steel work: 1215, 1045, and 4140. Each cuts and behaves differently, so we match the grade to strength, wear, and machining needs.

• 1215 steel is the free-machining carbon steel. Its higher sulfur content breaks chips cleanly, so it turns and drills fast with long tool life. It is the default for steel fasteners, spacers, and other high-volume turned parts that will not be welded.
• 1045 steel is a medium-carbon steel with a good balance of strength and machinability. It suits shafts, pins, and structural components that may be hardened later.
• 4140 steel is a chromium-molybdenum alloy steel. It offers high strength and toughness after heat treatment and is used for shafts, studs, and load-bearing parts. It machines harder than 1215, so we plan speeds and tooling accordingly.

Machining characteristics of steel machined parts

Carbon and alloy steels machine with a predictable balance between cutting speed and tool wear. Free-machining 1215 produces short, broken chips and holds tolerance easily, while 4140 is tougher and harder on tooling, especially in the heat-treated condition. We hold ±0.01 mm on precision features and work to ISO 2768-m as the general tolerance unless your drawing states otherwise.

Steel is stiffer than aluminum, so thin sections hold their shape better, but long slender shafts and studs still need support against deflection. We plan the cut sequence and tooling in DFM feedback, and every part is machined in-house on our own floor in Qidong, Jiangsu Province. Steel machined parts are the most cost-effective choice where strength matters and weight does not.

Typical parts made from this material

Steel covers the bulk of fastener and structural work. Common orders include carbon steel fasteners, shafts, studs, pins, and bushings.

• Steel bolts and steel nuts in 1215 or 4140, plus washers to match.
• Steel screws and threaded rods and studs for high-strength assembly.
• Shafts and pins in 1045 or 4140, often hardened and ground.
• Bushings and sleeves and spacers and standoffs for wear and alignment.

Orders start at 50 pieces per style and material, and a material certificate ships with every batch.

Surface finishes that pair well

Steel usually needs a protective or cosmetic finish because bare carbon steel rusts. Finishing is applied through our vetted partner network, managed under one quality process:

• Zinc plating — the standard corrosion coating for steel fasteners, available clear, yellow, or blue.
• Black oxide — a thin black finish for appearance and light corrosion resistance.
• Heat treatment — hardening and tempering for 1045 and 4140 where strength is specified.
• Nickel plating and chrome plating — where higher corrosion resistance or a bright surface is required.