A solenoid valve housing is not a container with a drawing attached. It guides an armature, carries magnetic flux, holds a seal face and survives pressure cycling for the life of the assembly. Buying one well means buying the material decision, the forming route, the annealing schedule and the inspection plan together.
What does Balford supply for solenoid valves?
Balford manufactures deep drawn and precision stamped components for solenoid valves, including housings, magnetic sleeves, frames, end caps, spring cups, washers and ferrules. Parts are produced from DC01/DC04 mild steel, 304 and 316L stainless steel, electrical pure iron and low-carbon soft magnetic grades on presses from 25 t to 350 t, with deep drawing up to 250 mm diameter. Secondary operations include magnetic annealing through qualified partners, CNC machining of seal faces and bores, deburring, passivation and plating. Balford is certified to ISO 9001:2015, runs controls aligned with IATF 16949 requirements, and submits PPAP Level 3 as standard for new programmes.
Material choice decides the magnetic behaviour
If the drawing does not specify magnetics, mild steel is usually the right default. If it specifies permeability, coercivity or a BH curve, the material and the annealing route both have to be controlled: deep drawing introduces cold work that raises coercivity and lowers permeability, so a housing drawn from electrical pure iron and shipped without annealing will not behave like the material datasheet.
- DC01 / DC04 mild steel — cost-driven housings where magnetics are not specified
- Electrical pure iron — where high permeability and low coercivity matter
- Low-carbon soft magnetic steel — defined magnetic specification with structural strength
- 304 / 316L stainless steel — corrosion resistance, but expect non-magnetic behaviour
- Brass and copper alloys — conductivity or corrosion resistance, usually machined or drawn
The tolerances that decide whether the valve works
Wall thickness uniformity, bore concentricity and roundness, seal face flatness and finish, overall length and flange position, and the bottom radius of the drawn shell. Features that govern sealing and armature movement are inspected with a 2.5D optical measuring projector, a vision measuring system, a digital height gauge, micrometres, three-point bore micrometres and concentricity gauges. Tight tolerances in the 0.001 mm range apply only to selected critical machined features where geometry, material and inspection conditions allow, and are confirmed from the drawing rather than promised as a blanket figure.
The failure modes worth inspecting for
- Cracking at the punch radius — a draw ratio, formability or lubrication problem that shows up at T1 samples
- Wrinkling on the flange or wall — insufficient blank holder force or a poor draw ratio
- Excessive wall thinning — tolerable in some designs, fatal in pressure-carrying parts
- Magnetic degradation after forming — cold work raises coercivity; annealing is not optional when magnetics are specified
- Leakage at the seal face — a finish or flatness problem, often introduced by handling or plating
- Plating defects — blistering, poor adhesion at edges and hydrogen embrittlement risk on high-strength parts
What to send with the enquiry
- Material grade, or the magnetic requirement if magnetics drive the design
- Wall thickness, and which tolerances are critical rather than reference
- Seal face finish requirement and surface treatment specification
- Annual volume and variant count
- Whether IMDS, PPAP Level 3 and material declarations are required
Key point
If a supplier quotes a solenoid housing without asking about magnetics, annealing, seal-face finish or plating control, they have quoted a cup — not a valve component.
Frequently asked questions
Does the housing material affect valve response time?
Yes. Materials with higher permeability and lower coercivity build flux faster and retain less residual magnetism, which affects both response and release behaviour.
Is stainless steel suitable for solenoid valve housings?
It is used where corrosion resistance matters, but most austenitic grades are non-magnetic, so they are unsuitable where the housing forms part of the magnetic circuit.
Should the housing be annealed?
If the specification includes magnetic performance, yes — deep drawing introduces cold work that degrades permeability, and magnetic annealing restores it within the limits of the material.
Can Balford machine the seal face after drawing?
Yes. Secondary machining of seal faces, bores and threads is carried out after forming, and tight tolerances are confirmed feature by feature during DFM review.