H68/H70 Brass

H68 and H70 are both widely used brass grades, especially in stamping applications. This article is written for buyers who are already in the RFQ stage or are currently screening suppliers for brass sheet metal parts. It covers the full path from basic material understanding to RFQ preparation.

H68/H70 Brass: Basic Overview

Both H68 and H70 are copper-zinc brasses, commonly referred to as standard brass. The main difference between them is copper content: H68 contains 67% to 70% copper, while H70 contains about 68.5% to 71.5%.

Even a small difference in copper content can lead to noticeable differences in performance, which is why this point deserves attention.

Both grades are single-phase alpha brasses. At room temperature, they have a single crystal structure and offer excellent ductility and forming toughness. That is one of the main reasons they are so widely used in sheet metal fabrication.

In some projects, H68 and H70 are considered side by side because their copper content is relatively close, and in many applications they can be used interchangeably.

304 stainless steel material display

Quick Identification Guide for H68/H70 Brass

Grade Material Category Common Supply Forms Common Application Areas
H68 Single-phase alpha brass (copper-zinc alloy) Sheet, strip, tube, bar Complex deep-drawn parts, housings, tubes, radiators, cartridge cases, terminals
H70 Single-phase alpha brass (copper-zinc alloy) Sheet, strip, tube, bar Sheet metal stampings, conductive parts, decorative parts, hinges, connectors

What Is the Difference Between H68 and H70 Brass?

The core difference between H68 and H70 has already been mentioned in the overview above. The sections below explain the specific differences in more detail.

Composition

The copper content difference between H68 and H70 is about 1% to 1.5%. That may look small, but it can still have a noticeable effect on the material. In general, higher copper content means better electrical conductivity, while ductility may be slightly reduced. For projects where conductivity matters, H70 is usually the better choice.

Formability

H68 is one of the most ductile brass grades. Its elongation can reach 35% to 45%, and its deep drawing ratio can reach 8:1. H70 typically offers elongation of around 30% to 35%. Its cold-forming performance is still very good, but for applications involving more complex deformation, H68 is generally the safer choice.

Strength

Both H68 and H70 are available in a range of tempers, from annealed to hard, to meet different tensile strength and hardness requirements. In the hard temper, H68 can reach a tensile strength of up to 660 MPa. H70 typically falls in the range of 470 to 560 MPa.

Electrical Conductivity

H70 has an electrical conductivity of about 28% IACS, while H68 is around 27% IACS. If your part needs both sheet metal formability and electrical function, H70 is the more suitable option.

H68 vs. H70 Brass Comparison

Comparison Item H68 H70 Material Selection Note
Copper content 67%–70% 68.5%–71.5% Difference is about 1%–1.5%
Ductility / elongation Excellent, 35%–45% Good, 30%–35% H68 is preferred for complex deep-drawn parts
Deep drawing capability Excellent, drawing ratio up to 8:1 Good, suitable for standard deep drawing Choose H68 for extreme deep-drawing requirements
Tensile strength, annealed ≥290 MPa 370–470 MPa Select based on strength requirements
Tensile strength, hard temper Up to 660 MPa 470–560 MPa High-strength tempers are easier to achieve with H68
Electrical conductivity About 27% IACS 38%–44% IACS Choose H70 first when conductivity matters
Thermal conductivity 116–121 W/(m·K) About 120 W/(m·K) The two are close
Weldability Good Better Both are suitable for standard welding applications
Typical part types Complex formed parts, thin-wall deep-drawn parts, precision housings Conductive parts, decorative sheet metal parts, standard stamped parts Choose based on part complexity and functional requirements

How to Read the Specifications for H68/H70 Brass

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Chemical Composition of H68/H70 Brass

Element H68 (%) H70 (%) Notes
Copper (Cu) 67.0–70.0 68.5–71.5 Primary element
Zinc (Zn) Balance, approx. 30–33 Balance, approx. 28.5–31.5 Alloying element
Lead (Pb) ≤ 0.03 ≤ 0.05 Impurity control
Iron (Fe) ≤ 0.10 ≤ 0.10 Impurity control
Nickel (Ni) ≤ 0.05 ≤ 0.05 Impurity control
Tin (Sn) ≤ 0.05 ≤ 0.05 Impurity control
Total other impurities ≤ 0.3 ≤ 0.3

Physical Properties of H68/H70 Brass

Temper Thickness Range Tensile Strength Elongation Hardness
O60, annealed soft 0.3 to 10 mm ≥290 MPa ≥40% HV ≤ 90
H01, quarter-hard 0.3 to 10 mm 325 to 410 MPa ≥35% HV 85 to 115
H02, half-hard 0.3 to 10 mm 355 to 440 MPa ≥25% HV 100 to 130
H04, hard 0.3 to 10 mm 410 to 540 MPa ≥10% HV 120 to 160
H06, extra hard 0.3 to 10 mm 520 to 620 MPa ≥3% HV 150 to 190
H08, spring temper 0.3 to 10 mm ≥570 MPa To be confirmed by agreement HV ≥ 180
M20, hot-rolled 4 to 60 mm ≥290 MPa ≥40% To be confirmed by agreement

Supply Forms and Tempers of H68/H70 Brass

Product Form Common Tempers What to Focus On
Sheet O60, H01, H02, H04 Housings, covers, deep-drawn parts, bent parts
Strip O60, H01, H02, H04, H06, H08 Terminals, spring contacts, progressive stamping parts
Bar H02, H04, and others Secondary machining, connectors, fasteners
Tube Annealed, hard temper, and others Tubes, heat-transfer-related parts, assembly components
Wire / flat wire O60, H00, H02, H04, and others Cold heading, fasteners, small conductive parts

What Sheet Metal Fabrication Processes Are H68/H70 Brass Suitable For?

Stamping / Blanking

Both H68 and H70 are very well suited to standard stamping, punching, and blanking processes. Within the usual sheet metal thickness range of 0.3 mm to 3.0 mm, cut-edge quality is generally stable. Both grades are also commonly used for complex cold-stamped parts and deep-drawn parts.

Bending and Forming

The bending performance of H68 and H70 depends mainly on the temper selected. In annealed and half-hard tempers, both grades can achieve relatively small bend radii, typically around one material thickness. For hard tempers, a larger bend radius of about 1.5 to 2 times the material thickness is generally recommended to reduce the risk of cracking on the outer surface.

Deep Drawing and Complex Cold Forming

Deep drawing and complex cold forming are among the strongest process advantages of H68 and H70. Both grades offer excellent ductility within the brass family and are especially well suited to housings, covers, and thin-wall deep-drawn parts. H70, with its higher elongation, tends to perform more consistently in parts with large drawing ratios. H68 is often preferred for deep-drawn parts that still need to retain a certain level of strength after forming.

Machining and Secondary Operations

Some stamped parts also require secondary operations such as polishing, tapping, deburring, or drilling after forming. H68 and H70 both offer good machinability and can deliver stable machining quality under standard processing conditions.

Process Compatibility of H68/H70 Brass

Process Type Suitability Key Considerations Typical Part Examples
Stamping and blanking Suitable Die clearance, burr control, hole-edge quality Washers, terminals, covers, contact strips
Bending and forming Suitable Temper, bend radius, springback Brackets, clips, enclosure frames
Deep drawing and complex cold forming H70 has a stronger advantage, though H68 is also widely used Drawing ratio, corner radius, lubrication, number of forming steps Housings, covers, tubes, bellows
Machining and secondary operations Suitable as a supporting process route Tapping, edge trimming, drilling, tolerance transition Post-stamping machined parts, assembly connectors
Welding and brazing High compatibility with brazing Joint cleanliness, heat effects, surface protection Tube assemblies, contact connection parts

Surface Finishing and Appearance Considerations for H68/H70 Brass

Common Surface Treatments and Typical Applications for H68/H70 Brass

Surface Treatment Main Purpose Suitable Part Types Items to Confirm in Advance
Nickel plating Corrosion resistance and wear resistance Fasteners, structural parts Coating thickness, sealing requirements
Tin plating Improved solderability and corrosion resistance Conductive parts, terminals Post-plating storage conditions, solderability testing
Silver plating Improved conductivity and appearance High-frequency connectors, contacts Coating thickness, anti-tarnish treatment
Gold plating Conductivity and reliability High-end connectors, precision contacts Cost considerations, coating thickness
Polishing High-gloss appearance Decorative parts, appliance panels Gloss level, uniformity
Brushed finish Textured surface appearance Electronic housings, panels Grain direction, texture fineness
Passivation / anti-oxidation treatment Short-term tarnish protection Stock parts, semi-finished parts Protection period, packaging method
Protective oil coating Medium-term corrosion protection Parts awaiting assembly Whether it affects subsequent assembly or welding

Common Applications for H68/H70 Brass

Application Scenarios and Material Selection Priorities for H68/H70 Brass

Part Type Typical Requirements Material Direction to Prioritize Design Note
Terminals, contact clips Conductivity, stamping performance, localized spring properties H70 Confirm strip temper and plating requirements first
Decorative covers, nameplates Appearance, flatness, surface consistency H68 or H70 Confirm the incoming sheet surface grade and protective film first
Thin-wall stamped parts High-volume stamping, hole-edge quality, assembly fit H68 Die clearance and burr direction should be confirmed in advance
Deep-drawn housings Deep drawing, smooth corner transitions, stable wall thickness H70 It is best to validate the drawing window with samples first
Tubes, bellows Formability, joining method, corrosion resistance H70 Pay close attention to the joining method and heat effects
Conductive parts with appearance requirements Formability, appearance, conductivity H70 Lock in conductivity, plating specification, and appearance standard together

What Information Should Be Confirmed Before Purchasing H68/H70 Brass Parts?

H68/H70 Brass RFQ Checklist

Information Category Required / Recommended Example Impact on Quotation or Evaluation
Material grade Required H68 or H70 Different grades vary in price and availability
Supply temper Required Annealed, half-hard, hard, or supplier-recommended Affects raw material sourcing and fabrication method
Incoming material size Recommended Sheet 1000 × 2000 mm, strip width 300 mm Affects material utilization and nesting layout
Finished part dimensions Required 200 × 150 × 5 mm Determines material consumption and processing time
Drawing revision Required REV.A or latest revision Ensures the technical requirements are aligned
Dimensional tolerance requirements Recommended General dimensions ±0.1 mm, critical dimensions ±0.05 mm Affects processing difficulty and inspection method
Quantity / batch volume Required First batch 500 pcs, monthly demand 2000 pcs Affects tooling allocation and unit price
Surface finish requirements Required Nickel plating 3–5 μm, or polishing to Ra 0.8 Usually outsourced, so it affects cost and lead time
Appearance standard Recommended No scratches, no press marks, uniform color A clear standard or approved sample should be provided
Inspection requirements Recommended Material certificate, 5% dimensional sampling Affects quality-control cost
Service environment Recommended Indoor dry environment, or outdoor humid environment Affects material choice and surface treatment
Lead time requirement Required Samples in 2 weeks, mass production in 4 weeks Affects production scheduling

FAQs​

The minimum bend radius depends heavily on the material temper and thickness. For annealed material, the bend radius can be as small as 0.5 times the material thickness, or even smaller, without cracking. For half-hard material, a bend radius of at least 1 times the material thickness is generally recommended. For hard temper material, the bend radius is usually recommended at 1.5 to 2 times the material thickness. One more factor also matters: the relationship between the bend direction and the rolling direction. When bending perpendicular to the rolling direction, the risk of cracking is higher, so a larger bend radius is usually needed. For complex parts with multiple bends, it is best to provide the drawing during the RFQ stage so the supplier can evaluate forming feasibility.

The scope of quality documents depends on customer requirements and project specifications. A basic mill certificate is usually available with the shipment and typically includes chemical composition and mechanical property data. If the project involves export requirements or industry-specific compliance, you may also request a RoHS test report, a REACH declaration, or a third-party inspection report. For cosmetic parts, it is recommended to confirm the appearance standard during sampling and keep an approved sample as the acceptance reference for mass production. Quality document requirements should be clearly defined during the RFQ stage, so additional testing later does not add lead time or cost.

Yes. For parts with conductivity requirements, specifying the grade alone is not enough. The material temper also needs to be confirmed. Within the same grade, conductivity can vary by 10% to 15% depending on the supply temper. This is because cold work hardening causes lattice distortion, which increases electron scattering and reduces conductivity. For example, a connector part that needs both formability and electrical performance may be specified only as “H70” in the RFQ. If the temper is not defined, the supplier may provide hard temper material, and the conductivity could end up lower than expected. It is better to state the required conductivity clearly in the RFQ, so the supplier can recommend the right temper, or add a low-temperature annealing step after forming if needed.

H68 and H70 offer good corrosion resistance in dry atmospheric and freshwater environments. In humid, high-salt, or marine environments, however, there is a risk of dezincification and stress corrosion cracking. If the part will be used in this kind of environment, the service conditions should be clearly communicated at the material selection stage. Common measures include using a modified H68A grade with a small arsenic addition to help suppress dezincification, applying plating or passivation on the part surface, and avoiding direct contact with other metals during assembly to reduce galvanic corrosion. In applications that are sensitive to stress corrosion, annealing after forming can reduce residual stress and lower the risk of cracking.

Lead time depends on several factors, including whether the required material temper and size are in stock, the complexity of the forming process, whether surface finishing needs to be outsourced, the order quantity, and the inspection requirements. For standard stamped parts with raw material already in stock, sample lead time is usually 7 to 14 days, and mass production typically takes 2 to 4 weeks. If the material requires a custom temper or imported sourcing, raw material lead time may add another 1 to 3 weeks. If outsourced surface treatment such as plating or anodizing is involved, lead time usually increases by an additional 3 to 7 days. It is best to define the required lead time in the RFQ so the supplier can provide an accurate production schedule based on current capacity.

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304 stainless steel material display
304 stainless steel material display
304 stainless steel material display
304 stainless steel material display
304 stainless steel material display
304 stainless steel material display
304 stainless steel material display
304 stainless steel material display