abrasive-wear

name	abrasive-wear
description	Abrasive wear — Archard wear law, two-body vs. three-body abrasion, hardness ratio, abrasion-resistant steels, ceramics, rubber liners, slurry wear, ASTM G65/G105/G75 testing.
metadata	{"priority":7,"promptSignals":{"phrases":["abrasive wear","wear resistance","abrasion resistant","Archard wear","slurry wear","erosion wear","wear rate"],"minScore":3}}

Abrasive Wear — Complete Skill

Wear Mechanisms

Two-body abrasion: hard asperity or particle slides against softer surface; grooving, ploughing Three-body abrasion: loose particle rolls/slides between two surfaces; lower wear rate than two-body (~1/3 to 1/10) High-stress grinding abrasion: particle crushed between surfaces; harder abrasive needed Low-stress scratching abrasion: particle slides; hardness ratio governs

Archard Wear Law

Volume worn: V = K × W × L / H [m³; K = wear coefficient; W = normal load [N]; L = sliding distance [m]; H = hardness of softer surface [Pa]]

Wear rate: Q = dV/dL = K × W / H [m³/m = m²]

Specific wear rate: k = K/H [m²/N = m³/(N·m)]

Wear coefficient K:

Wear pair	K
Unlubricated metals	10⁻³ – 10⁻²
Mild steel on hardened steel	10⁻⁴
Hardened steel on hardened steel	10⁻⁵ – 10⁻⁴
Ceramics	10⁻⁶ – 10⁻⁵
UHMWPE (polymer)	10⁻⁷ – 10⁻⁵

Hardness Ratio Effect

Critical hardness ratio: H_abrasive / H_material

• Ratio < 0.8: slight wear (ploughing only)
• Ratio 0.8–1.2: transition regime
• Ratio > 1.2: severe abrasive wear (cutting dominant)

Rule: material hardness should exceed abrasive hardness by ≥ 20% to achieve "slight wear" regime

Abrasive hardness reference:

Abrasive	Mohs	HV approx
Silica (quartz)	7	1100
Alumina (Al₂O₃)	9	2000
Silicon carbide	9+	2500
Diamond	10	8000

Wear-Resistant Material Selection

Abrasion-Resistant Steels

Brinell hardness (HB) and grades:

Grade	HB	C%	Notes
AR200	200	0.18	Mild; formable
AR400	400	0.30	Most common; good toughness
AR450	450	0.35	Higher wear resistance
AR500	500	0.40	Best AR steel; low toughness
Hardox 600	600	0.50	Ultra high hardness

AR400 wear life vs. mild steel: ~4× improvement in abrasion; ~2× in impact abrasion Hardfacing overlay: Chromium carbide (Cr₇C₃) on mild steel; HV 700–900; use where AR400 insufficient

White Cast Iron / High-Chromium Iron

High-Cr iron (15–28% Cr): M₇C₃ carbides; HV 700–900 Hardness: 550–800 HB; brittle (low toughness) Use for: pump impellers, crusher liners, mill liners

Tungsten Carbide Composites

WC-Co cermet: HV 1000–1500; excellent two-body abrasion; brittle against impact WC-Ni (corrosion resistant alternative to WC-Co) Use for: cutting tools, valve seats, slurry pump components

Ceramics (Alumina, SiC, Si₃N₄)

Al₂O₃: HV 1500–2000; chemical inert; use for fine particle abrasion SiC: HV 2500; high thermal conductivity; high-temperature abrasion Application: chute liners, cyclone liners, pipe elbows

Rubber Liners

Natural rubber: best for < 5 mm particle size; excellent energy absorption SBR, neoprene: corrosion + abrasion combination Shore A hardness 40–60 for maximum abrasion resistance Cut-off: use metal above 10–12 mm particle (rubber not effective for coarse rock)

UHMWPE

Ultra-high molecular weight polyethylene; excellent chemical resistance + abrasion Specific wear rate k ≈ 10⁻⁷ m³/(N·m); low friction coefficient (μ ≈ 0.1)

Slurry Wear

Erosion-corrosion wear in slurries: W_total = W_erosion + W_corrosion + W_synergy Synergy term: 20–60% of total loss in acidic slurries

Miller number (ASTM G75): standard test; higher number = more abrasive slurry

Slurry pump impeller material selection:

Application	Material
Coarse, non-corrosive	High-Cr white iron
Fine, corrosive	Duplex SS or rubber
Fine, high-pH	Natural rubber
High-T, coarse	Ni-Hard 4

Slurry velocity limits: Deposition velocity: V_c = F_L × √(2gD(S_s - S_l)/S_l) [Durand equation; F_L = 0.9–1.8; S_s, S_l = specific gravities; D = pipe ID [m]] Minimum: V ≥ V_c × 1.1 (operating margin) Maximum wear: V ≤ 3–4 m/s for dense slurries

Standard Tests

ASTM G65 — Dry Sand/Rubber Wheel: Load 130 N; 6000 rev; sand flow 300–390 g/min Reports volume loss [mm³]; relative volume loss vs. AR400 reference Discriminates: low-stress (non-impact) abrasion

ASTM G105 — Wet Sand/Rubber Wheel: Similar wheel test with slurry; simulates wet abrasion conditions

ASTM G75 — Miller Slurry Abrasivity: Standard specimen; reciprocating motion in test slurry; mass loss at 2 hr

ASTM B611 — Rotating Wheel with Abrasive Slurry: Wet abrasion using alumina slurry; ceramics and hard coatings

Field correlation factor: Lab wear rate (ASTM G65) × application factor (typically 3–10×) → field wear rate Factor depends on: impact severity, slurry concentration, corrosion, temperature

Design Rules

Chute/hopper lining: AR400 for most applications; use 500 or Hardox 600 where AR400 < 1 year life Target liner thickness: t = (D_particle / 10) × correction factor; minimum 10 mm Slope > 45° + material angle of repose for mass flow; eliminates dead zones

Pipe elbows (slurry): Use ceramic-lined (Al₂O₃) or replaceable liner; T-type for slurry (not standard elbows) Wall thickness: t = (V_slurry / V_max)² × t_base [proportional to velocity squared]

Impact angle effect (erosion): Ductile metals: max wear at 15–30° impact angle Brittle materials (ceramics): max wear at 90° (normal impact) Rubber: max wear at 90°

Output

Provide: wear mechanism classification (two-body/three-body/impact-abrasion), material hardness ratio vs. abrasive (H_mat/H_abrasive), recommended material and grade (AR400/AR500/WC-Co/Al₂O₃/rubber), ASTM G65 volume loss [mm³] for comparison, estimated wear rate [mm/year] at operating conditions, replacement interval [months], liner thickness [mm], slurry velocity vs. deposition limit (if slurry application), and relevant standard (ASTM G65/G75/G105).