Indonesia | H23Q100 GOES Solves Coating Peeling in S11 Transformer Cores

As power grid upgrade projects continue across Southeast Asia, S11 oil-immersed distribution transformers remain widely used in 20kV/0.4kV distribution networks. While magnetic performance is an important factor when selecting grain oriented electrical steel, coating adhesion, annealing compatibility, and material consistency are equally critical for transformer core production.

During core stamping, stacking, and stress relief annealing, insufficient coating adhesion may lead to coating peeling, reduced stacking quality, and higher production risks.

The customer is an Indonesian transformer core processor serving PLN grid upgrade projects.

The project used H23Q100 Common Grain Oriented Steel for:

• S11 oil-immersed distribution transformers
• Voltage rating: 20kV/0.4kV
• Capacity range: 100–1600kVA
• Power distribution infrastructure projects

These applications require stable material quality, reliable coating performance, and consistent supply support.

Before working with us, the customer sourced GOES through trading channels and encountered several recurring issues.

Some materials experienced coating adhesion degradation and peeling after 800°C stress relief annealing, affecting core stacking quality.

In addition, surface pits were occasionally found on incoming material, creating processing concerns during stamping operations.

The customer also faced unstable delivery schedules and quality inconsistencies from previous suppliers.

• Compliance with IEC 60404-8-8
• ISO 9001:2015 quality management system
• Coating adhesion Grade B or above
• Resistance to 800°C stress relief annealing
• EN 10204 Type 3.1 certification
• No surface pits allowed

Based on the customer's manufacturing requirements, we recommended H23Q100 Common Grain Oriented Steel with an inorganic insulation coating system.

Factory-measured coating adhesion data and stacking factor comparisons before and after annealing were provided to support material evaluation.

Considering Indonesia's humid tropical climate, recommendations were provided regarding material storage, annealing procedures, and coating protection to reduce processing risks.

A 20-ton trial order was arranged together with additional material for processing evaluation, allowing the customer to verify performance under actual production conditions.

Following production trials, the customer confirmed that H23Q100 met the requirements of transformer core stamping, stacking, and annealing processes.

The material maintained coating integrity during processing while meeting documentation and quality traceability requirements. Stable supply support also improved project planning and procurement reliability.

For S11 distribution transformer core manufacturing, material selection should go beyond magnetic performance alone. Coating adhesion, annealing compatibility, surface quality, and certification support are equally important considerations.

Key specifications of H23Q100 include:

• Thickness: 0.23 mm
• Strip Width: 400 mm / 600 mm
• Coating Adhesion: Grade B or Above
• Stress Relief Annealing Resistance: 800°C
• Standard: IEC 60404-8-8
• Certification: ISO 9001:2015 and EN 10204 Type 3.1

For transformer manufacturers seeking consistent core production quality, these parameters provide practical reference points for material selection and process stability evaluation.