ZL115 (ZAlSi5Zn1Mg) Cast Aluminum Alloy: Corrosion-resistant weldable alloy reinforced with zinc and magnesium composite
Date: 2026-03-11 Categories: Blog Views: 172
As a Chinese national standard (GB/T 1173) in theAluminum silicon zinc magnesium corrosion-resistant casting alloysThe characteristic representatives of theZL115 (ZAlSi5Zn1Mg) by means ofGood corrosion resistance, moderate mechanical strength and excellent weldabilityis known for. The alloy passesSilicon (Si) guarantees casting performance, reinforced by zinc (Zn) and magnesium (Mg) composite.The heat-treated products are particularly suitable for the manufacturing ofComplex castings requiring seawater corrosion resistance, weldability and medium loadsIt has a unique application value in the field of ships, chemical industry, food machinery and so on.
The national grade for ZL115 is ZAlSi5Zn1Mg.
- National Standard Grade: According to GB/T 1173, its grade isZAlSi5Zn1Mg. The name directly reflects its core alloy system: silicon (Si), zinc (Zn), and magnesium (Mg).
- Industry/Enterprise Code:ZL115 It is a widely used code for this material in foundry industry drawings, manuals and enterprise standards.
- Core features:Low to medium silicon content (4.5-5.51 TP3T) Ensure basic casting fluidity;Zinc (1.2-1.81 TP3T) complexed with magnesium (0.4-0.61 TP3T)Provides a reinforcing effect;copper-freeThis makes it possible to haveExcellent corrosion resistance; also hasGood weldabilityIt is one of the few cast aluminum alloys that is “corrosion resistant + weldable”.
ZL115 Aluminum Alloy Composition Table (based on GB/T 1173 typical requirements)
| elemental | Content range (wt%) | functional role |
|---|---|---|
| Silicon (Si) | 4.5-5.5 | Main alloying elements. Provides basic casting fluidity, partially solid solution strengthened. |
| Zinc (Zn) | 1.2-1.8 | One of the core enhancement elementsThe solid solution strengthening effect is significant. The solid solution strengthening effect is significant, while improving corrosion resistance. |
| Magnesium (Mg) | 0.4-0.6 | Key Enhancement Elements. Forms Mg₂Si with silicon, which synergizes with zinc to produce a composite strengthening effect. |
| Copper (Cu) | ≤ 0.1 | Strictly controlled impurities. Maintains excellent corrosion resistance. |
| Iron (Fe) | ≤ 0.6 | Impurity Element. Needs to be controlled, but tolerated moderately. |
| Manganese (Mn) | ≤ 0.5 | May be added to neutralize the harmful effects of iron. |
| Titanium (Ti) | 0.1-0.2 (can be added) | Grain refiner. |
| Aluminum (Al) | tolerance (i.e. allowed error) | Substrate material. |
ZL115 Physical and Mechanical Properties Parameter Table (metal mold casting, typical values)
| Performance indicators | Cast (F) | T5 aging state | T6 solid solution + aging state | Performance Positioning and Interpretation |
|---|---|---|---|---|
| intensity | 2.68-2.70 g/cm³ | -- | -- | -- |
| Tensile strength (Rm) | 160-190 MPa | 200-240 MPa | 250-290 MPa | T6 state strength is medium to high, meets general structural component requirements. |
| Yield strength (Rp0.2) | 90-110 MPa | 140-170 MPa | 180-210 MPa | Yield strength is increased after heat treatment and load carrying capacity is enhanced. |
| Elongation (A) | 3.0-5.0% | 2.0-4.0% | 2.0-4.0% | Good plasticityIt is superior to most copper-containing alloys. |
| Brinell hardness (HB) | 60-70 | 70-80 | 80-95 | Moderate hardness and good workability. |
| corrosion resistance | talented | talented | talented | Core AdvantagesIt is copper-free and resistant to corrosion by seawater and chemical media. |
| weldability | favorable | favorable | favorable | Core Advantages, can be tig-welded for repair and joining. |
| Casting mobility | moderate | -- | -- | Lower silicon content and less fluidity than high silicon alloys. |
| High Temperature Strength | general | general | general | Non-heat-resistant alloy, not suitable for long-term work at high temperatures. |
Performance Enhancement Pathways and Technical Characteristics
The ZL115“s performance comes from its "Zinc-magnesium composite reinforced, corrosion-resistant for this product”Design Concept:
- The unique role of zinc: Zinc has a high solid solubility in aluminum and can provideRemarkable solid solution strengthening effectand at the same time does not impair corrosion resistance as copper does. The addition of zinc also improves the alloy'snatural timeliness.
- Ancillary fortification with magnesium: Magnesium and silicon form Mg₂Si precipitated phases that are further strengthened by heat treatment. Zinc composite with magnesium forms reinforcing phases such as T(Al₂Mg₃Zn₃), which enhances the heat treatment response.
- Copper-free design: Strict limits on copper content ensure that alloys in marine and chemical environments areExcellent corrosion resistanceThis is the core feature that distinguishes it from copper-containing alloys such as ZL105 and ZL107.
- Good weldability: Due to the absence of copper and proper impurity control, ZL115'sLow tendency to weld hot cracksThe newest version of the TIG Welding System is the TIG Welding System, which allows for tig welding repairs and structural joints, facilitating the fabrication and repair of complex castings.
Corresponding international grades
The zinc-magnesium reinforcement system of ZL115 is somewhat unique internationally, but comparable grades can be found:
- Chinese national standard:ZAlSi5Zn1Mg (GB/T 1173)
- American Standard:: In conjunction with the 713.0 (Al-Zn6CuMg) system is different, but the 712.0 (Al-Zn6Mg) has some similarities; some sources mention that 771.0 (Al-Zn7Mg) system is similar. The closest is Zinc-containing aluminum casting alloys class, but there is no direct correspondence.
- EU standard:EN AC-41000 (Al-Si5Mg) Zinc free;EN AC-71000 (Al-Zn10Si8Mg) Excessive zinc content. No direct correspondence.
- Japanese Standard: No direct correspondence.
- international standard:AlSi5Zn1Mg Similar grades are available in ISO 3522.
ZL115 in the foundry industry
based on itsGood corrosion resistance, weldability and medium strengthfeatures, the ZL115 is mainly used in the following areas:
- Ship and Ocean Engineering (Core Applications)
- Marine Accessories: Deck valves, pump housings, pipe fittings, vent grilles.
- Marine platforms: Instrument holders, railing connectors, corrosion-resistant enclosures.
- Fishing Machinery: Fishing net winder housings, seawater pump components.
- Chemical and food machinery
- Chemical pumps and valves: Pump body, valve body, pipe fittings for conveying corrosive media.
- food machinery: Food processing equipment housings, conveyor pipe connections (no risk of copper contamination).
- Pharmaceutical equipment: Copper-free, corrosion-resistant instrument housings are required.
- General Mechanical and Structural Components
- Welded structural parts: Cast parts to be welded to aluminum profiles or plates.
- Complex housings: Instrument and meter housings and electrical equipment housings where corrosion resistance is required.
- rapid transit: Cabin interior trim pieces, armrest brackets.
ZL115 Aluminum Alloy Frequently Asked Questions
Q1: What is the most outstanding advantage of ZL115?
- Two core advantagesThe first isExcellent corrosion resistance(copper-free), especially resistant to seawater and chemical media corrosion; Secondly, theGood weldabilityIt can be connected and patched by argon arc welding. These two features make it uniquely valuable in marine, chemical and other fields.
Q2: What is the strength level of ZL115? How does it compare with ZL104?
- The tensile strength of ZL115-T6 is about 250-290 MPa.Slightly lower than ZL104-T6 (240-270 MPa, but typical values for ZL104-T6 are actually lower, upper strength limit for ZL104 is about 270, upper limit for ZL115 is about 290, so ZL115 is slightly higher or equivalent). However, ZL104 has better casting fluidity and ZL115 has better corrosion resistance and weldability. Both have their own focus, ZL115 is more suitable for the high corrosion resistance requirements of the occasion.
Q3: Why does ZL115 have good corrosion resistance?
- mainly becauseCopper (Cu) free. Copper in the aluminum alloy will form a cathodic phase, accelerating electrochemical corrosion.ZL115 strictly control copper ≤ 0.1%, while the addition of zinc instead helps to form a more stable surface oxide film, so that it shows excellent corrosion resistance in seawater, humid atmosphere and other environments.
Q4: What are the welding process requirements for ZL115?
- Good weldability, can be joined or repaired by conventional TIG (TIG/MIG) welding. Recommendation:
- Use welding wires with homogeneous or slightly higher properties than those of the base metal (e.g. aluminum-silicon wires containing zinc).
- Thoroughly clean the weld area before welding to remove oxide film.
- Appropriate preheating (100-150°C) is possible for thick and large pieces.
- Stress relief of important structural parts after welding.
Q5：Can ZL115 be used to manufacture marine propellers?
- unsuitablePropellers require extremely high strength and cavitation resistance, usually in nickel aluminum bronze or stainless steel. Propellers require very high strength and cavitation resistance and are usually made of nickel-aluminum bronze or stainless steel. zl115 is not strong enough and is mainly used for non-load-bearing or moderately load-bearing components in marine applications.
Q6：How is the casting performance of ZL115? What do I need to pay attention to when designing?
- medium level. The silicon content is only 4.5-5.5%, and the fluidity is not as good as ZL104, ZL111 and other high silicon alloys. Attention is needed when designing the casting system:
- Appropriately increase the size of the gate and increase the pouring temperature.
- Avoid excessively thin-walled structures (minimum recommended wall thickness ≥ 3 mm).
- Enhance the design of filler shrinkage to prevent shrinkage and loosening of shrinkage holes.
📊 Extended column: Comparative analysis of ZL115 and related alloys
| comparison dimension | ZL115 (AlSi5Zn1Mg) | ZL101A (AlSi7MgA) | ZL104 (AlSi9Mg) | ZL105 (AlSi5Cu1Mg) |
|---|---|---|---|---|
| Silicon (Si)% | 4.5-5.5 | 6.5-7.5 | 8.5-10.5 | 4.5-5.5 |
| Copper (Cu)% | ≤0.1 (without copper) | ≤0.1 (without copper) | ≤0.1 (without copper) | 1.0-1.5 (with copper) |
| Zinc (Zn)% | 1.2-1.8 | ≤0.1 | ≤0.2 | ≤0.3 |
| Magnesium (Mg)% | 0.4-0.6 | 0.25-0.45 | 0.17-0.35 | 0.4-0.6 |
| Tensile strength (T6) | 250-290 MPa | 290-330 MPa | 240-270 MPa | 280-320 MPa |
| Elongation (T6) | 2.0-4.0% | 3.0-6.0% | 1.5-3.0% | 1.5-3.0% |
| corrosion resistance | Excellent (no copper) | Excellent (no copper) | Excellent (no copper) | Medium (with copper) |
| weldability | talented | favorable | favorable | moderate |
| Casting mobility | moderate | favorable | talented | moderate |
| Typical Costs | moderate | mid-to-high-end | lower (one's head) | moderate |
Selection Quick Guide:
- Select ZL115: When the part requiresSeawater resistant, weldable, medium strengthWhen the time comes, it is a featured choice in the marine and chemical fields.
- Select ZL101A: RequiredHigher strength, good overall performanceWhen corrosion resistance is also required.
- Select ZL104: The QuestCasting manufacturability and economyWhen strength requirements are moderate.
- Select ZL105: RequiredHigh temperature strength or higher, Acceptable when corrosion resistance is slightly poorer.
