Mill liners are core wear-resistant components for ball mills in mining, building materials and power industries. They operate under harsh working conditions and demand high internal density and surface quality of castings. This liner is made of Mn13Cr2 high manganese steel, with a single casting weight of 1700kg and average wall thickness of 40–80mm, classified as a heavy-section wear-resistant casting.

In mass production with furan resin sand, castings of this type frequently encounter several technical challenges. First, sand molds for heavy-section castings need sufficient early strength to avoid deformation and box collapse during mold flipping and transportation. Second, the high tact time of flaskless molding production lines requires precise matching of resin bench life and stripping time. Premature curing will hinder sand filling, while delayed curing will reduce line efficiency. Third, high pouring temperature and large volume of molten steel for high manganese steel make the gas evolution and high-temperature stability of sand molds critical to prevent defects such as blowholes and sand burning-on.

In this case, FRH150 furan resin combined with HDS-04 curing agent is adopted for batch verification under the process of flaskless molding and metal mold. The test focuses on optimizing sand mold permeability and stripping efficiency to meet the mass production requirements of large wear-resistant castings on production lines.

Ⅰ. Product Information

Technical Indicators of FRH150 Furan Resin

Technical Indicators of HDS-04 Curing Agent

Ⅱ. Production Information

Ⅲ. Core Advantages of FRH150 Furan Resin and Matching Curing Agent

1. Low viscosity for easy sand mixing and uniform sand grain coating

   FRH150 resin has viscosity ≤40 mPa.s and HDS-04 curing agent viscosity ≤30 mPa.s. The two components feature good fluidity and can quickly and evenly coat sand grain surfaces during sand mixing. Consistent strength distribution across the sand mold avoids local weak zones that cause box collapse or sand wash.

2. Controllable curing speed matching production line tact time

   Under high-temperature conditions with sand temperature of 34℃ and ambient temperature of 31℃, the resin addition rate of only 0.92% and curing agent addition rate of 31% achieve precise matching of 6–7 minutes bench life and 30 minutes demolding time. It reserves enough operation window for sand filling while meeting the fast circulation requirement of flaskless molding lines.

3. Excellent permeability for uniform curing inside and outside heavy-section sand molds

   FRH150 resin features sufficient curing reaction. The large-size sand mold of 2200*1560*420mm achieves consistent curing throughout. Its tensile strength reaches 0.53MPa at 30 min and 0.92MPa at 8 h. The sand mold resists deformation and cracking during demolding, transportation and mold assembly.

4. Low free formaldehyde and low nitrogen formula, improving workshop conditions and casting quality

   FRH150 contains free formaldehyde ≤0.1%, which greatly reduces irritating odor and creates a friendly working environment. Nitrogen content ≤1.5% effectively lowers the risk of nitrogen blowholes in high manganese steel castings and improves internal casting density.

5. Good high-temperature stability suitable for high manganese steel pouring

   After curing, the resin retains high strength at elevated temperatures, withstanding long-time scouring by high-temperature molten Mn13Cr2 steel. It reduces sand wash and sand burning-on defects and cuts the workload of post-casting grinding.

Ⅳ. On-site Application and Result Analysis

The on-site production adopts a flaskless molding line with metal molds, and the sand mold dimension is 2200*1560*420mm. Under hot and humid summer conditions: sand temperature 34℃, ambient temperature 31℃ and humidity 66%, FRH150 resin is added at 0.92% and HDS-04 curing agent at 31%. The bench life of sand mixture stably remains at 6–7 minutes, and demolding can be completed within 30 minutes.

• Greatly improved demolding efficiency: With the same bench life, demolding time is shortened by 20–30% compared with traditional products. The output of sand molds per shift rises obviously, easing the tact bottleneck for large casting production lines.

• Stable sand mold strength: 30-min tensile strength of 0.53MPa meets the requirement for demolding and transportation. The 8-hour tensile strength reaches 0.92MPa, maintaining stable sand mold dimensions without deformation or cracking before mold assembly and pouring.

• Qualified casting quality: After pouring of Mn13Cr2 molten steel, the casting has smooth surface without obvious sand wash or burning-on. Internal inspection shows no nitrogen blowholes, and casting yield meets customer acceptance standards.

• Improved workshop environment: The low free formaldehyde formula significantly reduces irritating odor in the molding workshop, enhances comfort for frontline operators and complies with the development trend of green casting.

Xinda FRH150 furan resin and matching HDS-04 curing agent are specially developed for assembly line and large casting production. They deliver excellent permeability and demolding efficiency in flaskless molding and metal mold processes. The products are widely applied for wear-resistant castings such as mill liners and crusher jaw plates, as well as medium & large castings including machine tool beds and construction machinery structural parts for mass production.