HL105 Manganese Brass Brazing Strip: A Cost-Effective Choice for Copper and Copper Alloy Brazing

In the field of brazing copper and copper alloys, the melting point, fluidity, and joint strength of the brazing strip directly determine the connection quality. As a manganese-containing brass brazing filler metal, the HL105 manganese brass brazing strip, with its core characteristics of "medium-temperature brazing, excellent fluidity, and moderate cost," has become a mainstream material for connecting copper-to-copper and copper-to-steel dissimilar metals in industries such as refrigeration, plumbing, and hardware manufacturing. This article will comprehensively analyze the HL105 manganese brass brazing strip from dimensions such as basic characteristics, typical applications, operational specifications, and selection comparisons, providing professional guidance for copper alloy brazing operations.

I. Basic Characteristics and Core Advantages of HL105 Manganese Brass Brazing Strip

The HL105 manganese brass brazing strip complies with the GB/T 6418-2022 "Copper and Copper Alloy Brazing Filler Metals" standard and belongs to the Cu-Zn-Mn series brass brazing filler metal. Its core characteristics revolve around three dimensions: "composition design, melting point range, and process performance," with specific advantages as follows:

1. Composition Design: Balancing Strength and Corrosion Resistance

The composition ratio of HL105 is precisely optimized, with main components being 58%-62% copper (Cu), 30%-34% zinc (Zn), and 4%-6% manganese (Mn). This design imparts unique properties to the brazing strip:

•Strengthening Effect of Manganese: Manganese refines the weld grain structure, enhancing the joint tensile strength (room temperature tensile strength ≥300 MPa), which is more than 20% higher than that of ordinary brass brazing strips (e.g., HL101), allowing it to withstand certain loads;

•Optimized Corrosion Resistance: The synergistic effect of manganese and zinc reduces the oxidation rate of the weld in atmospheric and freshwater environments, with corrosion resistance superior to that of pure copper brazing filler metals, making it suitable for components such as civil pipelines and bathroom hardware that are long-term exposed to air;

•Composition Stability: The copper content is controlled at around 60%, avoiding an increase in melting point due to excessive copper content while ensuring compatibility between the weld and copper base material, reducing the formation of brittle interfacial phases.

2. Melting Point Range: Adapting to Medium-Temperature Brazing Scenarios

The solidus temperature of HL105 is approximately 870°C, and the liquidus temperature is approximately 900°C, classifying it as a medium-temperature brazing filler metal (800-950°C). This temperature range offers two major advantages:

•Avoiding Base Material Annealing Temperature: The annealing temperature of copper and copper alloys is mostly between 500-600°C. The brazing temperature of HL105 is higher than the base material annealing temperature but lower than the melting point of copper (1083°C), preventing performance degradation of the base material due to high-temperature softening;

•Compatibility with Mainstream Heat Sources: It is compatible with various heat sources such as oxy-acetylene flame, high-frequency induction heating, and resistance heating, eliminating the need for specialized high-temperature equipment and reducing equipment investment costs for small and medium-sized enterprises, making it particularly suitable for on-site repair operations.

3. Process Performance: Easy Operation and Strong Applicability

The process friendliness of HL105 is key to its widespread application, allowing even less experienced operators to quickly get started:

•Excellent Fluidity: The molten brazing material has strong fluidity, enabling full filling in narrow gaps of 0.1-0.3 mm, reducing "incomplete filling" defects, and making it suitable for brazing complex pipelines;

•Good Wettability: It exhibits excellent wettability on base materials such as copper, brass, and low-carbon steel, with a large spreading area (spreading rate ≥85% on copper surfaces), reducing the likelihood of "cold soldering" or "missed soldering";

•Aesthetic Formation: The weld surface is smooth after cooling, with no obvious pores or slag inclusions. Only simple polishing is required to meet appearance requirements, reducing the processing cost of hardware decorative parts.

II. Typical Application Scenarios of HL105 Manganese Brass Brazing Strip

Based on its characteristics of "medium-temperature brazing, high strength, and excellent corrosion resistance," HL105 is primarily suited for copper and copper alloys, copper-steel dissimilar metal medium-temperature brazing scenarios, with core application areas as follows:

1. Refrigeration and Air Conditioning Industry: Copper Pipe Connections

Copper pipe connections in condensers and evaporators of refrigeration and air conditioning systems require extremely high weld sealing and strength, which HL105's performance can precisely match:

•Typical Applications: Brazing of connecting copper pipes between indoor and outdoor air conditioning units, and butt welding of refrigerator evaporator copper pipes and dryer filters;

•Core Adaptation Points: Medium-temperature brazing prevents overheating and deformation of copper pipes, high-strength joints can withstand pressure during system operation (refrigeration system pressure is typically 0.5-2 MPa), and corrosion resistance ensures copper pipes do not rust in humid environments;

•Process Key Points: Before brazing, use sandpaper to remove the oxide layer on the copper pipe surface, apply borax-type flux (e.g., FB301), heat with an oxy-acetylene neutral flame, heat the thick-walled part first, and feed the brazing strip when the temperature reaches 870-900°C to ensure the brazing material fully fills the gap.

2. Pipeline Engineering and Bathroom Hardware: Civil Copper Component Connections

Civil pipelines and bathroom hardware require both sealing and appearance, where the advantages of HL105 are particularly prominent:

•Typical Applications: Splicing of civil copper water pipes, connection of brass faucets and water inlet pipes, and core brazing of copper radiators;

•Core Adaptation Points: Medium-temperature brazing is suitable for on-site construction, strong fluidity ensures pipeline sealing (no leakage in hydrostatic testing), and corrosion resistance meets the "5-year rust-free" usage requirement for civil pipelines;

•Precautions: Bathroom hardware components are mostly thin-walled (thickness 0.8-1.5 mm), so heating time must be controlled (single joint heating time ≤30 seconds) to avoid burn-through; after brazing, clean residual flux with hot water to prevent moisture absorption and subsequent weld corrosion.

3. Hardware Manufacturing Industry: Structural and Decorative Parts

Copper structural and decorative parts in the hardware manufacturing industry have high requirements for cost and appearance, where HL105's cost-effectiveness is significant:

•Typical Applications: Brazing of copper door lock components, connection of copper lamp brackets, and splicing of brass decorations;

•Core Adaptation Points: Cost is only 1/5-1/3 that of silver-based brazing materials (e.g., HL303), significantly reducing production costs; the weld formation is aesthetic and can be directly used as a decorative surface, reducing subsequent electroplating and painting processes;

•Process Requirements: When using high-frequency induction heating, control the heating power (adjusted to 5-15 kW based on component size) to avoid localized overheating and brazing material splatter; for decorative parts, apply anti-oxidant agents on the brazing strip surface to reduce weld discoloration.

4. Mechanical Repair Field: Copper Component Repair Welding and Dissimilar Connections

In equipment repair, HL105 can be used for repair welding of copper components and copper-steel dissimilar metal connections, addressing emergency repair needs:

•Typical Applications: Repair welding of copper gear tooth surfaces, crack repair of copper pump bodies, and connection of copper conductors and low-carbon steel terminals;

•Core Adaptation Points: Medium-temperature brazing is suitable for localized heating, avoiding damage to surrounding components; good compatibility with copper-steel dissimilar metals reduces interfacial corrosion, ensuring the service life of repaired components;

•Repair Key Points: Before repair welding, clean oil stains at the crack with acetone, and grind a V-groove with an angle grinder to ensure the brazing material fully fills; when connecting copper-steel components, pre-plate the steel surface with copper to improve brazing material wettability.

III. Standard Operation and Quality Control of HL105 Manganese Brass Brazing Strip

To fully leverage the performance advantages of HL105, it is necessary to follow the full-process specifications of "brazing strip management - base material pretreatment - brazing parameter control - post-weld treatment," with specific key points as follows:

1. Brazing Strip Storage and Pretreatment

HL105 brazing strips are prone to moisture absorption and oxidation, requiring strict control of storage and pretreatment:

•Storage Requirements: Unused brazing strips should be stored in a dry warehouse with temperature ≥10°C and relative humidity ≤60%, packaged in sealed bags (with desiccant inside), and avoid contact with oils and corrosive substances;

•Pretreatment: If an oxide film (appearing black) forms on the brazing strip surface, lightly sand with sandpaper until metallic luster is revealed to remove the oxide layer; no drying treatment is needed (brass brazing strips have weak moisture absorption), but they should be unsealed within 24 hours before use to avoid long-term exposure.

2. Base Material Pretreatment: Ensuring Weld Purity

Impurities on the base material surface can affect brazing material wettability and joint quality, making pretreatment steps essential:

•Surface Cleaning: Use 120-180 grit sandpaper to remove oxide scale and rust from the base material surface; wipe off oil stains with acetone or alcohol to ensure the welding area (brazing surface and within 10 mm surrounding) is free of impurities;

•Gap Control: Adjust the brazing gap according to component thickness, with a recommended gap of 0.05-0.2 mm (too small a gap may prevent brazing material filling, while too large a gap affects joint strength); for pipeline butting, use specialized clamps to ensure uniform gap.

3. Brazing Parameter Selection: Adapting to Different Scenarios

HL105 brazing parameters need to be adjusted based on base material type, component thickness, and heating method, with common reference ranges as follows:

•Parameter Adjustment Principles: Heating temperature should be 5-10°C above the liquidus temperature to ensure complete melting of the brazing material; heating time should be adjusted based on component thickness, with longer times for thick-walled parts (>3 mm) and shorter times for thin-walled parts (<1 mm) to avoid burn-through.

4. Post-Weld Treatment and Quality Inspection

Post-weld treatment is key to ensuring joint performance and appearance, requiring appropriate methods based on application scenarios:

•Post-Weld Treatment:

◦Cooling: Allow components to cool naturally to room temperature, avoiding water cooling (sudden cooling can cause internal stress in the weld, reducing strength);

◦Cleaning: Soak components in hot water for 10-20 minutes to remove residual flux (flux residue can absorb moisture and corrode the weld), then clean the surface with a brush;

◦Polishing: For components with high appearance requirements, lightly polish the weld with 240-400 grit sandpaper to improve surface smoothness;

•Quality Inspection:

◦Appearance Inspection: Weld surface should be free of cracks, pores, and incomplete filling, with reinforcement ≤1 mm and smooth transition to the base material;

◦Sealing Inspection: Pipelines and container components require hydrostatic testing (pressure at 1.5 times working pressure, held for 30 minutes with no leakage);

◦Strength Inspection: Important structural components should undergo sampling tensile testing to ensure joint tensile strength ≥300 MPa.

IV. Comparison of HL105 with Similar Brazing Strips: A Precise Selection Guide

HL105 is often confused with HL101 (ordinary brass brazing strip), HL303 (silver-based brazing strip), and HL201 (pure copper brazing strip). Selection should be based on core differences to avoid insufficient performance or cost waste:

•Selection Recommendations:

a.For civil pipelines, bathroom hardware, and medium-load copper components, prioritize HL105 to balance strength, corrosion resistance, and cost;

b.For low-load decorative parts and non-corrosive scenarios, HL101 is more economical (20% lower cost);

c.For industrial high-pressure pipelines and strong corrosive environments, upgrade to HL303 (silver-based brazing strip), though at higher cost;

d.For high-temperature conditions (>900°C), choose HL201 (pure copper brazing strip), but its high melting point requires specialized high-temperature equipment.

Conclusion

With its core value of "medium-temperature brazing, high strength, and high cost-effectiveness," the HL105 manganese brass brazing strip has become a "mainstay" in the field of copper and copper alloy brazing. Whether for copper pipe connections in refrigeration and air conditioning or brazing in civil pipelines and bathroom hardware, its performance meets the needs of most non-extreme scenarios. In practical applications, as long as base material pretreatment, brazing parameters, and post-weld treatment are strictly controlled, its advantages can be fully leveraged, ensuring reliable connections for copper components. For users seeking cost-effectiveness and operational convenience, HL105 is undoubtedly an optimal brazing strip that balances quality and cost.