Carbide Boring Bar Inserts

carbide boring bar inserts are cutting tool tips attached to boring bars used to accurately enlarge existing holes to precise diameters and finishes. Hard carbide grades and optimized insert geometries enable efficient boring operations on metals and alloys across industrial machining applications.

This guide covers boring insert specifications, boring bar system configurations, grades and coatings, operational parameters, quality considerations and advice on boring system component selection.

carbide boring bar inserts

carbide boring bar inserts Types

Common replaceable boring head inserts:

  • Singlesided square insert with multiple cutting corners
  • Double-sided square insert for rough boring applications
  • Single-sided round insert for finishing bores
  • Trigon insert with three cutting edges
  • Rectangle, rhombic, parallelogram other specialty shapes

Choose insert style based on hole size, tolerance needs and workpiece material. Larger neutral negative rake inserts withstand high feed rates well. Smaller inserts enable tight precision boring.

Boring Bar Toolholders

Carbide inserts precisely lock into these toolholder styles:

  • Solid type holders for stiffness and accuracy
  • Screw-on block type holders offering high versatility
  • Quick change style holders for fast insert indexing
  • Special boring bar holders with dampening features

Select toolholders to match insert shape securing it tightly without compromising precision. Consider vibration damping for optimal surface finishes.

Composition and Grades

Made from cemented carbides of:

  • Tungsten carbide (WC) providing wear resistance
  • Titanium carbide (TiC) for high toughness
  • Tantalum carbide (TaC) with good thermal properties
  • Niobium carbide (NbC) improving chemical resistance

Binder materials like Cobalt, Nickel and Chrome enable tailoring of hardness, toughness and heat resistance properties.

Common boring insert grades:

C2/C4HardBrittleFor soft workpieces <45 HRC. Low speeds, feeds.
C5/C6MediumStrongGeneral purpose finishing to semi-roughing
C7/C8Very hardBrittleHighly abrasive difficult to machine materials

Harder grades cut faster but are more prone to chipping requiring conservative operational parameters.

Geometric Characteristics

Lead angle/Nose radiusSharper < 20° or blunter > 30°Sharp is weaker but low cutting forces suitable for finish passes. Blunt is much stronger for rough boring able to take higher feeds/speeds
Rake anglesPositive/Neutral/Negative 0°- 25°More positive rake is better shearing but weaker edge. Negative rake stronger but requires higher cutting forces
Relief anglesDegree of back taper 5°- 15°Higher relief angles offer more wear resistance but compromise edge strength
Chip breakersVaried notch patterns on rake faceBreaks chips into small segments to prevent long continuous swarf tangling around tool

Properly match insert geometry to boring bar system rigidity, hole size precision needs and work material hardness characteristics balancing tradeoffs.

Insert Coatings

Common PVD, CVD coatings deposited onto carbide insert substrates to reduce friction and enhance heat resistance:

TiAlNTitanium aluminum nitrideHigh hardness and heat resistance. Wear protection ~700°C. General machining.
AlCrNAluminum chromium nitrideTougher coating than TiAlN, stable to higher temperatures 800°C+. Used for steels
TiNTitanium nitrideGold colored standard coating. Stable to ~500°C. Low friction good for aluminum, brass, bronze
TiCNTitanium carbon nitrideGood adhesion and lubrication. Used on ferrous metals and nickel alloys

Coatings help sustain sharp cutting edge and prevent built up edge. Check certification friction testing data. May use multiple layer combinations.

Work Materials

Hardness level determines suitable insert grades and operational parameters:

CategoryMaterialsHardness RangeInsert Grades
Soft low carbon steels, plasticCarbon steels, alloys steels through 45 HRC; stainless steels, inconels and titanium alloys, graphite composites, plastics.BHN 100-300. Under HRC 45C2, C4
Hardened steels and irons, titanium, hastelloysThrough hardened alloy steels 48-65 HRC; pearlitic, martensitic and tool steels; titanium & nickel iron superalloysBHN Over 300. HRC 48+C5, C6, C7+
Cast IronGray, ductile, malleable, compacted graphite120-450 BHNC6, C7, C8

Assess workpiece material specification hardness carefully before purchase. Harder materials require more precision in operational parameters to prevent premature edge chipping or insert breakage.

Cutting Parameters

ParameterFinishingMedium RoughingHeavy Roughing
Speed (SFPM)400-800600-1000800-1200
Feed Rate (IPR)0.0005-0.003”0.003-0.012”0.012-0.025”
Depth of Cut (IPM)Under 0.020”0.020-0.100”0.100-0.400”

Balance parameters relative to insert style and flank wear requirements to sustain sufficient material removal rates and precision bored finishes and geometries.

Industry Standards

  • ISO 1832:2012 – Numbering system for cutting tools
  • ANSI B212.4-1986 – Cutting tool inserts shape and size classification
  • ISO 513:2002 – Classification and application of hard cutting materials for metal removal with defined cutting edges
  • VDI 3323:2018 – Carbide boring bars – Design and application

Review statistical process control batch data against these and other global standards ensuring boring bar tooling quality.

Quality Metrics

  • Edge integrity
  • Consistent substrate and coating adhesion
  • Micro cracking prevention
  • Surface finish certification
  • Camber, thickness, form geometries
  • ISO certification on metalcutting performance

Validate performance consistency across batches, especially for custom boring programs.

Global Suppliers

Leading boring bar cutting tool manufacturers include:

  • [Mitsubishi Carbide]
  • [Kennametal]
  • [Korloy Inc.]
  • [Tungaloy America Inc]
  • [Iscar Metals Inc.]

Evaluate supplier consistency to quality metrics above supported by statistical batch data and customer references before purchase across locations.

Cost Considerations

carbide boring bar inserts range from:

  • $5 – $20 per insert for standard geometries and common sizes
  • $30+ for specialized custom insert designs and dimensions
  • $100+ for solid carbide one-piece adjustable boring heads

Compare rates across shortlisted vendors aligned to quantity and certification requirements. Consider custom boring needs but start testing with standard catalog inserts first to establish optimal grade and geometry.

carbide boring bar inserts

Buying Criteria

Technical DatasheetsHigh
Grade AvailabilityHigh

Vendor Comparison

ManufacturerRange OfferedLead TimesPricingTechnical Expertise
[Kennametal]Broad application coverageCustom quote 2 weeks100Industry leader with proven results
[ARCH®]Focus on steel boringStock ship within 5 days9Limited boring application experience
[TRUER]General boring needs2 week manufacturing50Wide range of indexable tooling lineup

Choose most experienced carbide boring bar cutting tool partner with stringent manufacturing quality systems aligned to work metals, hole specifications and delivery constraints.


Q: What is the best insert shape for precision boring bars?

A: Round inserts offer the most precise boring finish quality and dimensional accuracy for small boring bars, while triangular inserts maximize stiffness offering faster MRR in larger rough boring bars.

Q: How long do carbide boring bar inserts last?

A: Carbide boring life depends significantly on work material hardness and operating parameters. At conservative speeds, feeds and depths of cut, boring tool life between 60-90 minutes of cutting time can be expected from a sharp carbide insert.

Q: What causes early boring insert failure?

A: The main causes of premature boring insert breakage or rapid wear are insufficient rigidity in the boring bar system relative to operational forces and hardness or abrasiveness of the workpiece material requiring reduced feeds/speeds.

Q: How are boring bars resharpened?

A: Indexable inserts are designed to be replaced after dulling while the toolholder boring bar is reused indefinitely. Brazed tip bars may be detachable and retipped while solid carbide bars require grinding equipment to resharpen tips as needed over time.

know more Tungsten carbide

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