Hot-Dip Galvanized Bundy Tube with Double-Wall Construction for Corrosion Resistant Automotive Brake Systems

Price Negotiable

Price: 800-1000USD/Tom

MOQ: 1Ton

Delivery Time: 20-30days upon products

Brand: TORICH

Product Description

Galvanized Bundy Tube Hot-Dip Galvanized Precision Bundy Tube For Automobile Brake

Material

Galvanized Bundy tube is a double-wall, copper-brazed low-carbon precision steel tube designed for automotive fluid line service. In brake-line applications, the core value of this product is the combination of a compact double-wall structure, stable forming behavior, and protected outer surface for corrosion resistance. SAE J527 and ASTM A254 both describe this double-wall copper-brazed tubing family for automotive and similar line applications, while ISO 4038 covers metallic pipes used in hydraulic braking systems for road vehicles.

Specifications

Product type: Double-wall copper-brazed precision steel tube
Surface condition: Galvanized outer protection for corrosion resistance
Typical automotive brake-pipe outside diameters: 4.75 mm, 6 mm, 8 mm, and 10 mm
Processing capability: Suitable for bending, flaring, beading, forming, and brazing
Typical technical route: ASTM A254 / SAE J527 / ISO 4038 / DIN 74234 / JASO M101 / GOST 11249 / GB/T 34020.2

Main Features

Double-wall construction for higher structural reliability in brake-line service
Excellent bendability and flare consistency for vehicle pipeline forming
Corrosion-protected outer surface for improved service life
Precision dimensional control suitable for automotive line routing
Compatible with mainstream international brake-tube specification frameworks

Our Advantages

1. Designed around real brake-line forming requirements
Many buyers worry that low-cost tubing may split during bending or flaring. This product family is built on standards specifically intended for bending, flaring, beading, forming, and brazing, rather than on generic pipe language. That makes it a more credible choice for automotive brake lines and similar safety-related fluid routing.

2. Better corrosion-risk control for road service
Brake pipes are exposed to moisture, debris, and, in many markets, road salt. ISO 4038 requires the outer surface of brake pipes to be protected against corrosion and to withstand a neutral salt spray test for at least 96 hours. For procurement, this means buyers can define coating performance more clearly instead of relying on a vague “galvanized” description alone.

3. Easier multi-market sourcing and technical alignment
A major purchasing concern is whether one tube platform can support different export markets. This product family can be aligned with ASTM/SAE practice in North America, DIN/ISO brake-pipe references in Europe, JASO in Japan, GOST in CIS markets, and GB/T automotive double-wall tube practice in China. That helps OEM, aftermarket, and distributor buyers reduce approval friction across regions.

Chemical Composition

Grade	Standard / Reference Basis	C (%)	Si (%)	Mn (%)	P (%)	S (%)	Other Key Limits
BHG1	Q/BQB 494-2023	≤0.008	≤0.03	≤0.30	≤0.020	≤0.020	Alt ≥0.015
BHG2	Q/BQB 494-2023	0.015-0.06	≤0.03	≤0.30	≤0.030	≤0.030	Alt ≥0.015
ST12	DIN 1623 commercial reference	≤0.10	—	≤0.50	≤0.035	≤0.035	Alt ≥0.020
SPCC	JIS G 3141	≤0.15	—	≤0.60	≤0.100	≤0.050	Alloying additions may be added as required
10#	GB/T 699-2015	0.07-0.13	0.17-0.37	0.35-0.65	≤0.035	≤0.035	Cr ≤0.15, Ni ≤0.30, Cu ≤0.25

Mechanical Properties

Grade	Condition / Basis	Yield Strength (MPa)	Tensile Strength (MPa)	Elongation (%)	Remarks
BHG1	Q/BQB 494-2023	130-230	≥260	≥39	Strip reference for welded pipe use
BHG2	Q/BQB 494-2023	180-280	≥275	≥34	Strip reference for double-wall welded pipe use
ST12	DIN 1623 commercial reference	≤280	270-410	≥28	Common cold-rolled reference for simple forming
SPCC	JIS G 3141 reference	—	Usually not guaranteed unless ordered as SPCCT	Usually not guaranteed unless ordered as SPCCT	SPCC is commercial quality
SPCCT basis for SPCC guarantee	JIS G 3141	—	≥270	≥28 to ≥39 depending thickness	Mechanical guarantee route for SPCC when requested
10#	GB/T 699-2015, normalized reference	≥205	≥335	≥31	GB carbon steel reference, not finished brake-tube acceptance

Applicable Standards

Standard System	Reference	Brief Description
ASTM	ASTM A254 / A254M	Copper-brazed double-wall steel tubing for brake, fuel, oil, heating, and cooling lines
EN / DIN	DIN 74234	Hydraulic braking systems; brake pipes and flares
GOST	GOST 11249-80	Double-layer brazed steel tubes for hydraulic pipelines including automobiles
JIS / JASO	JASO M101:2022 / JIS G 3141	Automotive metal pipes for brake, fuel, and lubrication use; SPCC cold-reduced carbon steel sheet and strip
GB	GB/T 34020.2-2017 / GB/T 699-2015	Double-wall copper-brazed steel tubes for automobile tubing systems; 10# as quality carbon steel substrate reference

Application Fields

Automotive hydraulic braking systems
Used in hard brake lines between the master cylinder, ABS / ESC hydraulic unit, chassis routing sections, and wheel-end connections. ISO 4038 specifically addresses metallic brake pipes and fittings for hydraulic braking systems in road vehicles.

Automotive fuel and lubrication tubing
JASO M101 covers metal pipes for brake, fuel, and lubrication purposes, so the same Bundy tube platform can also serve selected automotive fluid-transfer circuits beyond braking.

General automotive and refrigeration line assemblies
ASTM A254 and SAE J527 both place this tubing family in automotive and similar line-service environments, including brake, fuel, oil, heating, and cooling circuits.

Aftermarket service and replacement kits
Suitable for repair, maintenance, restoration, and fleet-service use where stable bending and flare repeatability are critical for installation quality. This application is a practical extension of the brake-pipe forming requirements described in the relevant automotive tube standards.