GB Standard Industrial Carbon Steel Head

Updated: 2026-08-05

Overview

The GB Standard Industrial Carbon Steel Head is a hemispherical, elliptical, or dished component manufactured to China's GB/T 25198-2010 standard. It serves as an end closure for pressure vessels, ensuring leak-proof containment of gases or liquids under high pressure. Widely used in petrochemical, pharmaceutical, and energy industries, these heads are fabricated from grades like Q235, 20R, or 16MnR carbon steel. Their design adheres to strict geometric tolerances (±1% of nominal diameter) and surface finish requirements to withstand operational stresses.

Structure and Working Principle

Structurally, carbon steel heads consist of a curved shell with a flanged edge for welding to vessel bodies. Common types include hemispherical (for uniform stress distribution) and elliptical (2:1 ratio for balanced strength-to-cost performance). During operation, the head's curvature redistributes internal pressure loads radially, minimizing localized stress points. The GB standard specifies minimum thickness calculations based on design pressure, temperature, and corrosion allowance—typically ranging from 6mm to 50mm for industrial applications.

Key Features

GB-compliant heads undergo rigorous quality controls, including ultrasonic testing (UT) and radiographic inspection (RT) for weld joints. They feature a 12.5μm maximum surface roughness to prevent fatigue cracks. Manufacturers apply hot-forming or cold-spinning processes depending on thickness requirements. Post-fabrication heat treatment (e.g., normalizing at 890–950°C for 16MnR steel) ensures optimal mechanical properties, with typical yield strength exceeding 245MPa.

Application Areas

Primary applications include LNG storage tanks, reactor vessels in chemical plants, and steam boilers in power generation. The elliptical variant (EHA type) dominates 75% of industrial usage due to its cost efficiency. In offshore platforms, these heads withstand seawater corrosion when coated with epoxy or galvanized layers. Special food-grade versions with electropolished interiors are utilized in dairy and beverage processing equipment.

Maintenance and Precautions

Regular maintenance involves visual inspections for pitting corrosion every 6–12 months, with ultrasonic thickness measurements in high-erosion zones. Avoid abrasive cleaning methods that compromise protective coatings. Critical precautions include verifying weld procedure specifications (WPS) during installation and maintaining a minimum 5°C above the material's ductile-brittle transition temperature in cold environments. Always use compatible gasket materials (e.g., spiral-wound graphite for high-temperature service).

B2B Procurement Guide

When sourcing, prioritize suppliers with ASME or EN 13445 certification alongside GB compliance. Key procurement metrics include: 1. Delivery lead time (typically 15–60 days for custom sizes) 2. Mill test certificates for traceability 3. Dimensional inspection reports with actual vs. theoretical weight comparison Bulk orders (50+ units) often secure 8–12% price discounts. Consider third-party inspection services like SGS for critical applications.