C45 Cold Drawn Special-Shaped Profiles – Material, Drawing and Heat Treatment

We cold draw C45 special-shaped profiles from customer drawings. C45 is a medium-carbon steel with a carbon range of 0.42–0.50%. Cold drawing does two things at once: it forms the section you need, and it changes the mechanical properties of the steel. This page covers the material, the drawing process, the heat treatment options and the tolerances you can expect when you order a custom C45 profile.

Material: C45, 1045 or S45C

C45 is the same steel sold as 1045 in the AISI/SAE system and S45C in the JIS system. It sits above mild steel in carbon content, so it can be hardened by heat treatment, yet it still draws and machines cleanly in the annealed condition. Typical composition is 0.42–0.50% carbon, 0.50–0.80% manganese, 0.17–0.37% silicon, with phosphorus and sulfur each limited to 0.035%.

How Cold Drawing Changes C45

The starting point is hot rolled or rolled-forged C45 bar. We pickle it to remove scale, then pull it through a die shaped to your section. Drawing work-hardens the outer layer of the steel: yield and tensile strength rise, the surface gets harder and the section holds a tighter tolerance than rolled steel of the same nominal size.

That change matters for design. A drawn C45 profile comes to you with higher strength than the same section hot rolled, so you can often reduce section size or weight. The trade-off is a harder surface layer and lower ductility than annealed C45. If the profile is machined later, that work-hardened skin machines away quickly, and you are left with a clean, uniform cross-section.

Mechanical Properties by Delivered Condition

C45 responds differently depending on how it is supplied. The table below shows typical values for each condition we deliver. Final values are confirmed on the mill test certificate for your batch.

Most buyers of drawn C45 profiles take the as-drawn condition and machine to finish. Specifying quenched and tempered profiles makes sense when the section itself is the load-bearing part and you want to skip a heat treatment step at your end.

Heat Treatment Options

As drawn – hardness 170–210 HB, ready to machine. This is the standard condition for profiles that are machined into finished parts.

Normalized – refines the grain and evens out properties across large sections. Specify this when the profile is thick or when you need consistent machinability across a long bar.

Quenched and tempered – hardness can be specified, commonly 28–32 HRC or 35–40 HRC, for wear parts and load-bearing components. Hardness is verified on the finished profile before packing.

Tell us the delivered condition you need. If you plan to harden the part yourself after machining, we supply as drawn and you control the final hardness.

Machinability and Cutting Practice

C45 in the annealed or as-drawn condition machines predictably. Machinability is around 65% of a free-cutting grade, which is normal for a medium-carbon steel: expect slightly higher cutting forces and shorter tool life than on 1214 or 1215, but no special coolant or tooling is required. Carbide inserts with a light positive rake and a consistent feed hold the surface finish on drawn profiles.

Hardness is the factor that decides cutting practice. At 170–210 HB the steel is in the sweet spot for machining – soft enough to cut cleanly, hard enough to give a good finish. If you take quenched and tempered profiles at 28–40 HRC, plan for finishing operations rather than heavy removal.

Induction Hardening After Drawing

C45 is a common choice for induction hardening. The drawn profile is machined to finish, then the working surface is heated by an induction coil and quenched. Case hardness of 50–58 HRC with a hardened layer of 1–3 mm is typical for C45, depending on frequency and power. The drawn surface works well as the base for induction hardening because the section is consistent and free of scale.

If your application needs a hard wear surface on a soft core, tell us during the drawing review. We confirm the section has enough material for the case depth you need.

What Sections We Can Draw

We draw sections within 3–120 mm width and 2–80 mm thickness, up to 12,000 mm long. Typical shapes are trapezoidal bars, keystone sections, rails with undercuts, dovetail profiles, T-sections, L-sections and customer-specific designs.

Section geometry controls drawability. A simple trapezoid or keystone draws cleanly on the first try. Deep grooves, very thin walls and sharp internal corners need a die design review first: we check the width-to-thickness ratio and the wall thickness in the narrowest part, and tell you before tooling whether the section can be drawn in one pass or needs a preform. This review costs nothing and prevents a die that does not fill.

Tolerances, Straightness and Twist

Tolerances follow EN 10278 or GB/T 905 for drawn sections, or your drawing where it is tighter. Straightness is held to 1 mm/m or better depending on section. Twist – the rotation of the section along its length – is controlled by the drawing and straightening setup and checked on long profiles. We measure the finished profile against your drawing, not against a nominal table, because a custom section only fits your assembly if the drawing dimensions are met.

The Drawing Process, Step by Step

1. Drawing review. We check your drawing for drawability: section dimensions, tolerance, corners, surface requirement and quantity. If the section needs a design change to draw cleanly, we say so and propose an alternative before tooling starts.

2. Die preparation. The drawing die is machined to your section from tool steel, sized to account for springback in the drawn bar.

3. Trial draw. A short trial run is drawn and checked against the drawing. Dimensions, corners and straightness are verified before production starts.

4. Production. The full order is drawn, straightened, cut to length and inspected. Hardness and dimensions are recorded per batch.

5. Packing. Bars are bundled, oiled if required, and protected for sea freight.

First-time orders take 20–30 days including die preparation. Repeat orders run faster because the die is already made.

Drawn Profile vs Machined from Solid

For a non-standard section, you have two routes: draw it, or machine it from a standard bar. Drawing moves the metal to the final shape in one operation, so the cost per metre falls quickly once the die exists. Machining removes metal and scrap at every piece, and it gets expensive on long profiles. A drawn profile makes sense from a few hundred metres per year; below that, machining may be cheaper. We quote both routes when a customer is unsure.

Where C45 Profiles Are Used

C45 drawn profiles go into machine tooling, conveyor rails and slides, hydraulic guide systems, wear parts and transmission components. The combination of medium-carbon strength, a bright drawn surface and a section that matches your design is the reason buyers choose a drawn profile over machining a standard bar down to shape. The draw does the rough work; you machine only the functional faces.

Quality and Documentation

Every order carries an EN 10204 3.1 mill test certificate with chemical composition, mechanical properties and dimensional results. Hardness is reported for heat-treated profiles. Third-party inspection is arranged on request.

What We Need to Quote a Custom Profile

To quote accurately we need: the section drawing (with dimensions and tolerances), the material grade and condition, length and quantity, and the intended use if the section is difficult to draw. Send these and we come back with a quote and a delivery date. We also draw special-shaped profiles in other grades, round bar and square bar on the same lines.

Design Recommendations for Drawn C45 Sections

Designing a section that draws well keeps your die cost low and your tolerance reliable. Three rules cover most cases. Keep corners as generous as the design allows: a 0.5–1 mm radius at internal corners helps the die fill and reduces stress on the drawn skin. Keep the section balanced – a symmetric section draws straighter than a heavily asymmetric one. And keep the thinnest wall above about 2 mm for a medium-carbon grade like C45; below that, drawing forces concentrate and the section can neck or tear. If your design cannot follow these rules, send it to us anyway – we review drawability before tooling and suggest a workable alternative.

Packaging and Delivery

Drawn profiles are delivered cut to your length, deburred, bundled and steel-strapped. For sea freight we oil the surface when rust protection is required and wrap bundles against container humidity; cut pieces go into wooden crates when the quantity is small or the section is delicate. Stock and repeat orders ship within 10–15 days of confirmation; first-time tooled orders take 20–30 days. We quote delivery against your port.

Where C45 Special-Shaped Profiles Are Specified

Agricultural machinery. Rake bars, guide sections and wear strips in harvesters and balers are typical C45 profile jobs. The drawn section is the working profile – straight, to size, and ready for local induction hardening on the wear surface. This saves the fabricator from milling the profile from plate or bar.

Machine tool components. Slides, gibs and guide sections for machine tools use drawn profiles because the consistent cross-section and straightness cut the fitting work. C45 gibs and slides are supplied as drawn for final scraping or light grinding.

Locking and clamping sections. Wedge profiles, clamping bars and quick-release sections are drawn to the working shape in C45, with the sharp edges and angles held to the drawing. The drawn surface is ready for use, so the part goes straight to cutting and drilling.

Inspection on profiles. Custom sections are checked with profile gauges and dimensional measurement against the approved drawing; the first piece of each lot is verified before the line runs. EN 10204 3.1 certificates are issued per order on request.