1. Applicable Standards & Product Application Scope

This low-friction composite brake block complies with two official Korean specifications:

1. National General Standard: KS R 9237:2023 Composition Brake Shoes for Railway Rolling Stock, stipulating mandatory universal indexes for friction, mechanical strength, thermal resistance and environmental protection;

2. Korea Railroad Operation Specification: KRCS B006 06 Technical Specification for Railway Supplies-Brake Shoes, customized for Korean domestic freight wagons and metro vehicles with exclusive installation dimensions, wear resistance and line test requirements. Exclusive restricted application limits of Korean standard brake block:

· Brake mounting structure: Compatible with Korean standard 2×Bg single-side single block brake bogie;

· Maximum allowable axle load: 23 tons;

· Maximum vehicle operating speed: ≤110km/h;

· Matching wheel diameters: Standard Korean steel tread wheels 710mm / 760mm / 840mm;

· Applicable lines: Domestic trunk freight lines, underground tunnel metro and elevated suburban light rail in Korea, adapting to high humidity and winter low temperature (-35℃) operating environments;

· Interchange logic: Replicate braking force curve of Korean cast iron brake blocks for retrofitting existing vehicles without basic brake system modification, different from high-friction blocks which require brake lever replacement.

2. Structural & Localized Material Composition

(1) Friction Contact Surface

Asbestos-free modified phenolic resin organic composite matrix optimized for humid Korean tunnel conditions, reinforced with aramid fiber and mineral fiber, mixed with high-purity graphite long-acting solid lubricant and antimony sulfide friction modifiers. Free of asbestos, lead, cadmium and other restricted heavy metals, no carbonization or irritating flue gas under long-term humid and continuous high-temperature braking. Dynamic friction coefficient stably ranges 0.14~0.18, friction fluctuation ≤±16% under all working conditions, complying with KS R 9237 friction stability limits. Curved contact surface precisely fits standard R420 tread radian of Korean wheels to achieve full uniform contact during braking, drastically reducing wheel tread corrosion, scuffing and spalling risks in humid tunnel environments. Fine internal buffer micropores absorb braking impact and eliminate high-frequency squeal noise during low-speed station approaching and rainy humid operation. All edges are thickened and passivated to adapt to bumpy mountain railway lines in Korea, preventing chipping, cracking and corner peeling during long-term service.

(2) Steel Back Base

Stamped integrally from 4.5~5mm Q235 cold-rolled low-carbon steel plate. Multiple trapezoidal anchor grooves are pressed on the inner side; friction compound deeply embeds into grooves during hot molding to reach KS-standard bonding strength, preventing delamination and chipping under long-term cold & hot cyclic and long downhill heavy-load braking. The steel back surface is treated with anti-rust phosphating to resist high humidity and salt spray in Korean underground tunnels and delay corrosion failure. Exclusive Korean standard single integrated buckle at the bottom perfectly fits domestic universal brake shoe holders for easy maintenance replacement. The steel back is equipped with wear warning boss: continuous abnormal metal friction noise occurs when friction layer wears down to safety limit of 12mm to remind mandatory full block replacement, eliminating safety hazard of steel back grinding wheel tread.

3. Mandatory Performance Requirements per KS & KRCS

1. Friction Stability: Friction coefficient fluctuation ≤±16% under normal temperature, rain immersion, long downhill continuous braking and -35℃ extreme cold environment, without obvious cold or thermal fading; passed 30-minute continuous drag durability special test by Korea Railroad Research Institute;

2. Thermal Resistance: Max continuous operating temperature 325℃, instantaneous peak temperature 430℃ under wheel lock emergency braking, no bubbling, carbonization or layered cracking failure;

3. Long-Term Wheel Protection: Wheel tread wear reduced by over 48% compared with traditional Korean cast iron blocks; wheel-rail equivalent conicity strictly controlled, wheel profile inspection required every 22,000 km to avoid vehicle hunting instability risks;

4. Full Track Circuit Compatibility: Low-conductivity non-metallic composite formula generates no hard metal debris to interfere with Korean railway signal transmission, passing full KRCS track circuit compatibility inspection;

5. Moisture, Rust & Noise Control Performance: Phosphating anti-rust treatment on steel back for tunnel high humidity and salt spray resistance; braking noise decreased by 9~17dB(A) versus cast iron blocks, complying with Korean rail transit noise control regulations;

6. Eco-Friendly Safety Performance: Zero asbestos, low heavy metal formula, biodegradable braking dust with no underground tunnel pollution, fully compliant with Korean K-REACH environmental control requirements.

4. Application Scope, Maintenance & Storage Rules

1. Applicable Rolling Stock: Korean standard trunk open wagons, covered wagons, container freight wagons, Seoul/Busan metro and suburban light rail vehicles, uniformly matched with 2×Bg single-side single block brake bogies;

2. Mandatory Replacement Standard: Full brake block replacement required when residual friction thickness ≤12mm; grinding, splicing and secondary reuse are strictly prohibited;

3. Running-in Operation Rule: Stable low-speed operation within the first 500km after installation, avoid frequent emergency braking to realize uniform fitting of friction surface; full-load long downhill continuous braking forbidden during running-in period;

4. Storage Condition: Store in dry & ventilated warehouse, avoid long-term dampness and open-air rain soaking, stacking height ≤10 layers, shelf life 18 months;

5. Mandatory Inspection Cycle: Wheel equivalent conicity inspection every 22,000 km during routine operation, simultaneously check friction layer cracking, partial uneven wear and chipping defects.

5. Core Differences Between Korean Standard Low-Friction Blocks & UIC LL Low-Friction Blocks

1. Governing Standards: Korean standard follows KS R 9237 & KRCS B006 06; UIC series follows UIC Leaflet 541-4;

2. Working Condition Adaptation: Korean formula customized for domestic high-humidity tunnels and -35℃ low temperature with anti-rust & moisture-proof design; UIC blocks optimized for European 40‰ steep gradient cross-border freight lines;

3. Load Capacity Limit: Korean standard max axle load 23t, max speed 110km/h; UIC Notation #3 supports up to 27.5t axle load and 120km/h speed;

4. Mounting Compatibility: Korean blocks only fit domestic 2×Bg single-side brake structure; full UIC LL series compatible with both 2×Bg and 2×Bgu double-side configurations;

5. Friction Tolerance Range: Korean standard allows friction fluctuation ±16%; UIC enforces stricter ±15% fluctuation limit.

Low-friction synthetic brake block–Korea Standard