How C3604 Brass works: a practical explanation
C3604 Brass is a free cutting brass with lead, the standard choice for turned parts that have to be fast to make. It is used for fittings, connectors and turned components where machinability drives the cost. This entry explains what it is, what the numbers on a data sheet mean, and what to put on a drawing.
It is written from the point of view of the buyer and the drawing office: the values that are realistic in production, the ones that cost money, and the way the result is verified. Where an industry sets the requirement, oil and gas is used as the example: materials that work harden and still have to be certified.
How it works, step by step
- The part or the material is prepared, and the datum features are established.
- C3604 Brass is applied under the parameters below, with the result checked against the drawing.
- The measured value is fed back as an adjustment, so the next part starts from a known condition.
- The finished work is inspected and documented: standard dimensional inspection.
The numbers that matter
| Specification | Typical value |
|---|---|
| Tensile strength | 450 MPa |
| Yield strength | 200 MPa |
| Hardness | 120 HB |
| Density | 8.50 g/cm³ |
| Machinability | excellent, the reference against which others are rated |
| Corrosion resistance | good, with dezincification in some waters |
Where it stops working
Every process has a limit, and for C3604 Brass the practical one is cost. Material cost is moderate, and the cycle time is the lowest of any metal, so a specification that pushes past it is usually a specification that should be written differently.
Applications
C3604 Brass is used for fittings, connectors and turned components where machinability drives the cost, and in practice it appears most often in plumbing fittings, electrical connectors, instrument parts, valve bodies.
How it fits into a machining route
C3604 Brass is chosen at the drawing stage, and everything downstream follows from it: the tool geometry, the cutting data, the heat treatment and the certificate. Changing the grade later is a different part, not a different quote.The route is fixed before the first part is cut, and it is the route rather than the individual setting that holds the result: material cost is moderate, and the cycle time is the lowest of any metal. Where a drawing calls for something the route cannot hold economically, that is raised at quotation rather than after the parts are made.
Standards, documentation and what is issued
The documentation requirement is EN 10204 3.1 available, RoHS exemption noted where required. Material is supplied against a certificate where the application calls for it, inspection results are recorded with the job, and the records are kept so that a repeat order can be compared with the first instead of being measured from scratch.
Standard dimensional inspection is the verification step. Where a customer format or a standard report is required, it is agreed before the batch starts, because a report written after the event is a report nobody can use.
Frequently asked questions
What tolerance should be specified for C3604 Brass?
±0.01 mm is realistic in production. Tightening it beyond the functional requirement increases cost without improving the part.
Which material is usually used?
C3604 brass is the usual choice, supplied against EN 10204 3.1 available, RoHS exemption noted where required.
How is the result verified?
Standard dimensional inspection, with the results recorded so a repeat order can be compared with the first.
What is the most common mistake?
Assuming it is as strong as steel, because it is not.
How long does it take and what does it cost?
A realistic cycle is very fast, with excellent chip breaking, and the cost driver is material cost is moderate, and the cycle time is the lowest of any metal.
Related capability
If you are specifying C3604 Brass on a drawing and want a second opinion on the route, send the model and the quantity. The first response is a manufacturability review with the likely risk points and a quotation, so the decision can be made on facts rather than on a price alone.
Machining, inspection and documentation are handled in one place, which is why the dimensional report and the material certificate arrive with the parts rather than after them.
Related entries
These entries sit next to C3604 Brass in the encyclopedia: Duplex 2205 Stainless Steel, 4140 Alloy Steel, Hydraulic Manifolds. Reading them together gives a fuller picture of how the process, the material and the measurement affect each other.
