Carbon & Tool Steel FeCl₃+HCl

Chemical Etching Formula
65Mn Spring Steel with FeCl₃+HCl

This reference describes how 65Mn Spring Steel responds to the FeCl₃+HCl etching formula. At a bath temperature of 48°C and concentration of 44 °Bé, the recipe holds an etch factor of about 2.72 and a typical production yield of 97.1%. It is intended as engineering reference data for design, sourcing, and process planning.

Formula Summary

The table below summarizes every parameter that defines this etching formula. Values listed as ranges scale with sheet thickness across the supported band.

FeCl₃+HCl Etchant System
44 °Bé Concentration
1.410 Specific Gravity
48 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.5 mm Thickness Range
0.13 mm Typical Thickness
0.12-73.48 m/min Conveyor Speed Range
0.84 m/min Typical Speed
8-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
1-92 μm Undercut Range
2.72 Etch Factor (EF)
97.1% Typical Yield (96.2-97.4%)

Why FeCl₃+HCl for 65Mn Spring Steel?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like 65Mn Spring Steel. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on 65Mn Spring Steel is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Bath control for 65Mn Spring Steel in FeCl₃+HCl: temperature 48°C, concentration 44 °Bé, specific gravity 1.410. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.12-73.48 m/min across the supported thickness range. Check specific gravity each shift with a calibrated hydrometer and correct with fresh make-up or water as needed.

Design Rules & Tolerances

Design rules for this recipe: hole diameter 8-600 μm, line width 100-500 μm, single-side undercut 1-92 μm — all as a function of thickness across 0.01-0.5 mm. The higher the etch factor (this formula holds about 2.72), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.

Design Rule Summary
• Minimum hole diameter range: 8-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 1-92 μm
• Typical etch factor (EF): 2.72

Yield & Production Economics

Expect a yield in the 96.2-97.4% range for 65Mn Spring Steel with FeCl₃+HCl, with 97.1% typical on a well-controlled line. Most rejects trace back to upstream coating and exposure rather than to the etch bath itself, so tightening photolithography control is usually the fastest path to a higher number.

Typical Applications

65Mn Spring Steel etched with this recipe typically ends up in spring elements, blades, shim stock, and stamped-replacement flat parts. Because chemical etching applies no mechanical or thermal load, the finished features are free of work-hardening and heat-affected zones — a decisive advantage over stamping or laser cutting for these uses.

More Carbon & Tool Steel Formulas

Other formulas in the same material family.

50CrV4 Spring Steel FeCl₃+HCl Through etch (double-sided) 65Mn Spring Steel FeCl₃+HCl Half etch (single-sided) DT4 pure iron FeCl₃+HCl Through etch (double-sided) SK2 Tool Steel FeCl₃+HCl Through etch (double-sided) SK3 Tool Steel FeCl₃+HCl Through etch (double-sided) SK5 Tool Steel FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Run the bath at 48°C. Holding much above 53°C can degrade photoresist adhesion and erode feature edges; running below 43°C slows the etch and forces a conveyor-speed reduction. Production lines hold 48°C within ±1.5°C using redundant PID control.

Need a Quote for This Process?

WET Etched runs production wet chemical etching lines using the FeCl₃+HCl chemistry. Send us your part drawing and quantity for a full process quote.

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