Instant Quote

Compare 1018 vs 4140 steel strength machinability cost and best uses with our detailed alloy selection guide.

1018 Steel: What It Is and Why It Matters

When engineers compare 1018 vs 4140, 1018 is the go‑to low carbon “workhorse” mild steel: cheap, easy to machine, easy to weld, and predictable.

Chemical Composition of AISI 1018

AISI 1018 steel is a plain, low carbon steel with very limited alloying.

ElementTypical Range (wt%)
Carbon (C)0.15 – 0.20
Manganese (Mn)0.60 – 0.90
Phosphorus (P)≤ 0.04
Sulfur (S)≤ 0.05
Iron (Fe)Balance

Key point: Low carbon = excellent ductility, weldability, and machinability, but limited hardenability compared with 4140 chromoly alloy.

Mechanical Properties of 1018 (Typical, As‑Rolled/Cold Drawn)

Values vary by form and condition, but typical ranges:

cURL Too many subrequests.Typical Value
Tensile strength~ 440 – 500 MPa (64 – 73 ksi)
Yield strength~ 370 – 415 MPa (54 – 60 ksi)
Elongation~ 15 – 25%
Hardness~ 120 – 170 HB
Modulus of Elasticity~ 205 GPa (29,700 ksi)

Performance profile:

  • Moderate strength vs alloy steels
  • High ductility and good impact toughness
  • Stable and predictable for general fabrication

Workability, Machinability, and Weldability

Compared to cURL Too many subrequests., cURL Too many subrequests.

  • cURL Too many subrequests. cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.

  • cURL Too many subrequests. rounds, squares, flats, hex (hot rolled & cold drawn)
  • Plates & sheets: hot rolled, pickled & oiled, cold rolled
  • Structural shapes: limited; for pure structural we often move to other structural grades
  • Condition options:
    • Hot rolled
    • Cold finished (better surface and tighter tolerance)
    • Peeled/turned and ground for shafting

We support:

  • Cut‑to‑length
  • Saw cutting, precision cutting
  • Mill certs and full traceability on request

When 1018 Mild Steel Is the Right Choice

Choose 1018 over 4140 alloy steel when:

  • Loads are low to moderate and not fatigue‑critical
  • Cost and availability matter more than maximum strength
  • You need easy machining and welding with minimal fuss
  • Parts will be case hardened rather than through‑hardened
  • You want tight dimensional control via cold‑finished bar

Typical 1018 steel applications include:

  • Brackets, plates, base frames
  • Light shafts, pins, bushings (non‑critical)
  • Welded fabrications and structural components
  • Machined fittings, spacers, jigs, and fixtures

If you’re unsure whether 1018 vs 4140 is safer for your load and duty cycle, I usually start with your required yield strength, fatigue life, and budget and size the section from there before recommending the grade.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests.. cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

ElementcURL Too many subrequests.cURL Too many subrequests.
CcURL Too many subrequests.cURL Too many subrequests.
MncURL Too many subrequests.cURL Too many subrequests.
CrcURL Too many subrequests.cURL Too many subrequests.
MocURL Too many subrequests.cURL Too many subrequests.
Si0.15 – 0.35%Strength, deoxidation
P, S≤ 0.035%Kept low for toughness

Those Cr-Mo additions are the big difference vs 1018 and are why we call 4140 a chromium molybdenum alloy (chromoly) steel.

Mechanical Properties & Strength Profile of 4140

Properties vary a lot with heat treatment. Typical ranges:

ConditionYield Strength (MPa)Tensile Strength (MPa)Hardness (HB)
Annealed415 – 655655 – 895~ 187 – 217
Quenched & Tempered655 – 1030+850 – 1250+~ 248 – 320

Key points:

  • Much stronger than 1018 at the same size
  • Can be tailored from tough/ductile to very high strength with proper tempering
  • Good strength-to-weight for shafts, gears, and high‑load parts

If you care about how strength connects to machining accuracy, it pairs well with tight‑tolerance processes like milled steel machining where precision and stability really matter (see our guide on what milled steel is and how it’s machined).

Hardenability, Toughness & Fatigue Resistance

Why 4140 is a “go‑to” high‑strength alloy:

  • Excellent hardenability
    • Through‑hardens in thicker sections vs simple carbon steels
    • Uniform properties across the cross‑section
  • Good toughness
    • cURL Too many subrequests.
    • cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests.
    • cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
  • cURL Too many subrequests.
    • Annealed cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
    • Nitriding for wear and fatigue resistance

When 4140 Alloy Steel Is the Better Choice

Choose 4140 vs 1018 when:

  • The part sees high loads, torque, or shock
    (shafts, gears, couplings, spindles, tool holders)
  • You need higher fatigue life and long‑term durability
  • You need hard, wear‑resistant surfaces but still want a tough core
  • The cost of failure is high (downtime, safety, warranty risk)
  • You want to reduce section size/weight without sacrificing strength

In short:
Use 1018 for low‑stress, general fabrication.
Step up to 4140 when strength, hardenability, and fatigue resistance are critical to your design or your customer’s uptime.

1018 vs 4140: Side‑by‑Side Comparison

Both grades are solid choices, but they solve different problems. Here’s the quick, practical breakdown.

Tensile Strength & Yield Strength: 1018 vs 4140

Typical room‑temperature values (round bar, approximate):

cURL Too many subrequests.1018 (as‑rolled)4140 Annealed4140 Q&T ~28–32 HRC4140 Q&T ~38–42 HRC
Tensile strength (MPa)~440–480~655–745~930–1030~1100–1250
Yield strength (MPa)~320–350~415–450~760–860~900–1050
  • If you’re under 300 MPa working stress, 1018 is usually enough.
  • cURL Too many subrequests. high load, shock, or safety‑critical parts, cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.cURL Too many subrequests.cURL Too many subrequests.
cURL Too many subrequests.cURL Too many subrequests.Low
cURL Too many subrequests.cURL Too many subrequests.cURL Too many subrequests.
cURL Too many subrequests.cURL Too many subrequests.Medium
cURL Too many subrequests.cURL Too many subrequests.High
cURL Too many subrequests.cURL Too many subrequests.Very high
  • Use 1018 cURL Too many subrequests. cURL Too many subrequests..
  • Use 4140 cURL Too many subrequests. continuous wear, impact, and fatigue matter.

Machinability & Weldability: 1018 vs 4140

Machinability (relative to free‑cutting steel = 100):

GradeMachinability RatingNotes
1018~70–78Very easy to machine
4140 Annealed~65OK with correct tooling
4140 Q&T40–60 (drops as HRC rises)Needs rigid setup, sharp tools

cURL Too many subrequests.

  • 1018:
    • Excellent weldability with MIG, TIG, stick.
    • No preheat for most thicknesses.
  • 4140:
    • Preheat (typically 150–300°C) and controlled cooling required.
    • Higher risk of cracking, needs low‑hydrogen process and proper filler.

If your process is weld‑heavy and shop skills vary, 1018 is lower risk. For cURL Too many subrequests. of hard parts, 4140 works fine if you control tools, speeds, and coolant—similar to what’s needed in precision CNC machining of hard materials as discussed in our ceramic CNC machining guide.

Heat Treatment Response & Hardenability: 1018 vs 4140

  • 1018 steel (AISI 1018):
    • Very low carbon (~0.18% C) = not through‑hardening.
    • Only useful heat treatment: carburizing / case hardening + quench.
  • 4140 chromoly alloy (chromium molybdenum steel 4140):
    • Medium carbon (~0.40% C) + Cr + Mo = high hardenability.
    • Responds extremely well to:
      • Normalizing
      • Quench and temper (Q&T)
      • Induction hardening
    • Can achieve a wide range of strength and hardness profiles.

If you need through‑hardened shafts, gears, or bolts, 4140 wins every time.

Cost, Availability & Sourcing

cURL Too many subrequests.cURL Too many subrequests.cURL Too many subrequests.
cURL Too many subrequests.cURL Too many subrequests.cURL Too many subrequests.
AvailabilitycURL Too many subrequests.cURL Too many subrequests.
cURL Too many subrequests.cURL Too many subrequests.cURL Too many subrequests.
  • 1018 cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
  • 4140 cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.:

  • cURL Too many subrequests. rust without protection.
  • Typical protection methods:
    • Painting or powder coating
    • Zinc plating, phosphating, black oxide
    • Oil / grease for internal or temporary protection

For parts that must survive harsh environments, plan cURL Too many subrequests. regardless of 1018 vs 4140.

Weight, Tolerance & Dimensional Stability

Density is almost identical:

cURL Too many subrequests.10184140
Density (g/cm³)~7.87~7.85

Weight difference is negligible at part level.

Main differences:

  • 1018:
    • More ductile, more forgiving during forming.
    • Less distortion during welding.
  • 4140:
    • More prone to movement during heavy machining and heat treatment.
    • Needs stress‑relieving to maintain tight tolerances on long shafts or thick sections.

cURL Too many subrequests. tight tolerance, heat‑treated parts, it’s critical to combine proper heat‑treat control with reliable material testing and traceability—exactly the type of support we bundle with our projects, aligned with the best practices outlined in our comprehensive material testing guide.

In simple terms:

  • 1018 = easy to machine, easy to weld, cheap, for low–medium stress.
  • 4140 = strong, hard, fatigue‑resistant, but needs more process control.

Applications: Where 1018 Shines vs Where 4140 Excels (1018 vs 4140 / 1018 与 4140)

Best applications for 1018 mild steel in general fabrication

AISI 1018 mild steel is my go‑to when you need easy machining, easy welding, and low cost:

  • Brackets, frames, base plates, and fixtures
  • Jigs, simple tooling blocks, alignment plates
  • Pins, bushings, spacers, sleeves with low to moderate loads
  • Welded fabrications, support structures, light machine parts
  • Shafts and couplings where strength demands are modest and failure isn’t critical

If your main goals are cURL Too many subrequests., cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.

  • cURL Too many subrequests.
  • cURL Too many subrequests.
  • cURL Too many subrequests.
  • cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.

  • 1018cURL Too many subrequests.
  • 4140cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests., 4140 usually wins. If it just needs shape and stiffness, 1018 keeps cost down.

Industrial machinery, tooling, and oilfield: 4140‑first applications

Industrial and oilfield users lean hard on 4140 because of its strength and fatigue life:

  • Hydraulic cylinder rods, tie rods, press rams
  • Tool holders, collets, and spindle components (often machined on a vertical machining center)
  • Drill collars, subs, rotary components, and downhole tools
  • Heavy machine shafts, couplings, gear blanks, and flanges

If your machine runs long hours under cyclic load, 4140 quenched and tempered is usually the starting point.

Structural, brackets, and low‑load parts: 1018‑first applications

cURL Too many subrequests. general structural work and light duty parts, I default to 1018:

  • Welded frames, racks, tables, and guards
  • Bracketry, mounting plates, hinge plates, and tabs
  • Light supports, housings, covers, and non‑pressurized manifolds

It welds clean, distorts less than higher‑carbon steels, and keeps material cost under control.

Hybrid strategies: mixing 1018 and 4140 in the same system

A practical, cost‑driven approach is to mix 1018 and 4140 in one assembly:

  • Use 4140 for high‑stress components (shafts, gears, load‑bearing pins, wear points)
  • Use 1018 for support, alignment, and mounting (frames, brackets, plates, non‑critical spacers)

This way you pay for 4140 only where its strength, wear resistance, and fatigue performance actually matter, while 1018 keeps project budgets and lead times in check.

Fabrication Guide for 1018 vs 4140

Machining 1018: Speeds, Feeds, Tooling

AISI 1018 mild steel is very forgiving to machine. It cuts cleanly, holds size well, and is ideal for CNC prototypes and general production.

Basic tips for machining 1018:

  • Tooling:
    • HSS works for low‑volume; carbide for higher speed and long runs.
    • Use sharp, positive‑rake tools to avoid built‑up edge.
  • Cutting speeds (rough guide):
    • HSS: 25–35 m/min (80–120 SFM)
    • Carbide: cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests. cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

4140 annealed (~HB 197):

  • Easier to machine than hardened, but still tougher than 1018.
  • Cutting speeds:
    • HSS: 15–25 m/min (50–80 SFM)
    • Carbide: 90–150 m/min (300–500 SFM)
  • Use rigid setups, sharp carbide, and constant coolant.

4140 quenched & tempered (QT, HB 248–302+):

  • Much harder, higher tool wear, needs more control.
  • Cutting speeds (carbide): 60–110 m/min (200–360 SFM)
  • cURL Too many subrequests.
    • Strong, negative‑rake carbide inserts
    • Small DOC and moderate feeds
    • Plenty of coolant or high‑pressure through‑tool coolant
  • Avoid chatter: maximize rigidity, minimize tool overhang.

If you’re new to machining 4140 QT, start conservative on speed, then tune for tool life and surface finish.

Welding 1018: Processes and Filler Choices

1018 welding is straightforward and very forgiving.

Best processes:

  • MIG (GMAW): Fast, easy, great for structural and brackets.
  • TIG (GTAW): For cleaner, cosmetic, or precision welds.
  • Stick (SMAW): Good for field work and thicker sections.

Fillers:

  • MIG: ER70S‑6 solid wire
  • TIG: ER70S‑2 / ER70S‑6 rod
  • Stick: E6010/E6011 for root, E7018 for structural work

No preheat needed for typical thicknesses. Just keep:

  • Clean base metal (remove mill scale, oil, rust)
  • Reasonable interpass temperatures to avoid distortion.

Welding 4140: Preheat, Post‑Heat, Cracking Control

4140 alloy steel is not weld‑like‑1018 material. It’s hardenable and prone to cracking if you treat it like mild steel.

Key rules:

  • Preheat:
    • Typical: 150–315°C (300–600°F) depending on thickness and restraint.
    • Thicker and higher strength (QT) needs higher preheat.
  • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests..

cURL Too many subrequests.

  • cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests., cURL Too many subrequests.
  • cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests.. cURL Too many subrequests.

Typical Q&T workflow:

  1. Normalize (optional): 870–925°C (1600–1700°F), air cool to refine grain.
  2. Austenitize: ~830–870°C (1525–1600°F).
  3. Quench: Oil quench (common). For small sections, polymer or water can be used with care.
  4. Temper:
    • 200–300°C (390–570°F): very high hardness, lower toughness.
    • 400–600°C (750–1110°F): balanced strength/toughness, common for shafts and gears.
    • 600–675°C (1110–1250°F): lower strength, high toughness.

Always match hardness/strength level to real loads; over‑hardening 4140 is a common fatigue failure trap.

Case Hardening 1018: Carburizing Options

1018 has low carbon, so through‑hardening is weak – but it excels at case hardening.

Carburizing options:

  • Pack or gas carburizing:
    • 900–950°C (1650–1750°F), carbon‑rich atmosphere.
    • Case depth usually cURL Too many subrequests., depending on time.
    • Follow with oil quench + temper for a hard shell with a tough core.
  • Carbonitriding (for smaller parts):
    • Adds nitrogen + carbon; useful for wear‑resistant small components.

Use case‑hardened 1018 for pins, bushings, low‑load gears, and wear faces that need a hard skin but not full‑section strength.

Forming, Bending, and Cutting: 1018 vs 4140

Forming & bending:

  • 1018:
    • Excellent formability.
    • Cold bending, rolling, and forming are easy with minimal cracking.
    • Great for brackets, frames, and formed sections.
  • 4140:
    • Annealed: formable, but needs higher force than 1018.
    • QT: limited cold forming; cracking risk. Hot forming is safer.

Cutting:

  • 1018:
    • Saws, laser, plasma, and waterjet cut cleanly.
    • CO₂ lasers work well for standard plate and sheet.
    • Ideal for custom sheet parts and car sheet metal repair components.
  • 4140:
    • Tougher on blades; use quality bandsaw blades and slower speed.
    • For QT 4140, waterjet or high‑power laser is preferred to reduce HAZ hardness.

In practice, I push 1018 for formed and welded structures, and lean on 4140 where machining, heat treatment, and long‑term fatigue performance matter most.

1018 vs 4140: Pros and Cons for Real‑World Projects

When I choose between AISI 1018 steel and 4140 chromoly alloy, cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

  • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests.
  • cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests. cURL Too many subrequests.

cURL Too many subrequests.

  • cURL Too many subrequests. – lower steel tensile strength 1018 and yield strength than 4140.
  • Limited heat treatment response – you can case harden 1018, but not through‑harden like 4140.
  • Poor wear resistance – not ideal for sliding, rotating, or impact‑loaded wear surfaces.
  • Lower fatigue resistance – not suited for highly cyclic or shock‑loaded parts without oversizing.

Use 1018 when your part is simple, lightly loaded, or when cost and ease of fabrication matter more than maximum strength.

Advantages and Disadvantages of 4140 Steel

Pros of 4140 alloy steel

  • cURL Too many subrequests. – significantly higher mechanical properties of 4140 steel (tensile and yield) than 1018.
  • Great hardenability – responds very well to quenched and tempered 4140 bar and induction hardening.
  • High wear resistance – especially in 4140 normalized vs quenched and tempered conditions.
  • Good fatigue resistance – ideal for alloy steel for gears and shafts, spindles, axles, and tools.
  • Better toughness when treated correctly – strong yet not brittle if heat treated right.

Cons of 4140 steel

  • Harder to machine – especially in higher hardness; needs good tooling and cutting strategy.
  • More demanding to weld – requires preheat, controlled cooling, and often post‑weld heat treatment.
  • Higher material cost – more expensive than 1018, plus added cost for heat treatment.
  • Less forgiving – mistakes in machining, welding, or heat treatment can lead to cracking or distortion.

Use 4140 when your part sees real loads, torque, impact, or long‑term fatigue – for example in automotive, oilfield, and heavy machinery.

cURL Too many subrequests.

cURL Too many subrequests.

  • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
    • cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
      • cURL Too many subrequests.
      • cURL Too many subrequests.
      • cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests., cURL Too many subrequests. cURL Too many subrequests..

cURL Too many subrequests.

cURL Too many subrequests. 1018 vs 4140, I look at four things:

  • Static load
    • Low to moderate load, lots of safety margin → 1018 steel is usually enough.
    • High load, torque, or bending stress → lean toward 4140 chromoly alloy.
  • Fatigue and shock
    • Rare or low‑cycle loading → 1018 can work.
    • Continuous cyclic loading, impact, or vibration → 4140 is safer.
  • Wear conditions
    • Little to no wear, or sacrificial parts → 1018 is fine.
    • Sliding contact, gear meshing, or rotating shafts → 4140 wear resistance wins.
  • Budget and process capability
    • Tight cost targets, basic shop equipment, simple welds → 1018.
    • Higher budget, access to heat treatment and better machining → 4140.

Quick Decision Checklist: 1018 or 4140?

Use this as a fast filter when deciding 1018 vs 4140（1018 与 4140）:

Choose 1018 if:

  • The part is mainly structural, bracket, fixture, or low‑load.
  • You need easy machining and welding.
  • You’re working to a strict budget and high volume.
  • Little or no heat treatment is planned.

Choose 4140 if:

  • The part is a shaft, gear, spindle, axle, coupler, or high‑stress pin.
  • You need high tensile strength and yield strength, with good fatigue life.
  • You require heat treatable 4140 steel for hardness and wear resistance.
  • Safety, long life, and reliability matter more than lowest cost.

If you’re between the two, I usually start with 1018 for low‑risk parts and step up to 4140 once the design moves into critical, rotating, or high‑load territory.

Frequently Asked Questions About 1018 vs 4140 (1018 与 4140)

Is 4140 stronger than 1018 in typical applications?

Yes. In most real‑world parts, 4140 chromoly alloy is significantly stronger than AISI 1018 mild steel.

  • 1018 (as-rolled): tensile ~440–480 MPa, yield ~250–320 MPa
  • 4140 cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.

  • cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
  • cURL Too many subrequests. through‑hardened cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. 1018 vs 4140 cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. AISI 1018 steel and 4140 alloy steel, cURL Too many subrequests.

  • cURL Too many subrequests. with heat numbers and chemical composition
  • Mechanical property reports (tensile strength, yield strength, hardness)
  • Clear traceability from mill → warehouse → your PO
  • Material that meets ASTM, AISI, SAE and EN specs where required

That means when you compare 1018 vs 4140 mechanical properties, you’re working with certified data, not guesswork.

Stock Range, Cutting & Heat‑Treat Services

I keep a wide range of:

  • 1018 and 4140 in round bar, flat bar, plate, block, tube
  • Standard and close‑tolerance sizes for CNC and machining shops

On top of that, we can:

  • Cut‑to‑size for quick production
  • Supply 4140 in annealed, normalized, or quenched and tempered (QT)
  • Arrange heat treatment (quench & temper, stress relief, or case hardening for 1018) so parts go straight to machining

If you’re running a tight machining workflow, you’ll likely benefit from our experience with CNC precision engineering and tolerance control, similar to what’s covered in this practical CNC precision engineering guide with processes and applications.

Technical Support from Metallurgists & Engineers

Choosing between 1018 vs 4140 isn’t just about strength charts. My team can help you:

  • Pick the right grade based on load, fatigue, and budget
  • Decide between 4140 normalized vs quenched and tempered
  • Tune machinability, weldability, and heat treatment to your process
  • Avoid over‑engineering with 4140 or under‑spec’ing with 1018

You get real feedback from people who live in the world of alloy steel for gears and shafts, fixtures, brackets, and high‑stress parts.

cURL Too many subrequests.

cURL Too many subrequests. 1018 vs 4140:

  1. cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
  2. cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.
  3. cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests.
    • cURL Too many subrequests. cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests. cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests. 1018 vs 4140, you’ll usually want to compare them against a few other core grades and have quick reference data on hand. I keep it simple and practical.

1018 vs 1045 and Other Carbon Steel Grade Comparisons

For general fabrication and turned parts, most shops are really comparing these three:

GradeTypeTypical Use Case
1018Low carbon / mild steelBrackets, fixtures, shafts, weldments
1045Medium carbonStronger pins, axles, basic shafts
4140Alloy steel (Cr‑Mo)High‑load shafts, gears, tooling

Quick rule of thumb:

  • 1018 – easiest to weld and machine, lowest strength.
  • 1045 – middle ground, can be heat treated, more strength.
  • 4140 – highest strength and hardenability in this group, for demanding parts.

4140 vs Other Alloy Steels for Gears and Shafts

For gears, spindle shafts, and drive components, the real battle is 4140 vs other alloy steels like 4130, 4340, or case‑hardening grades.

GradeKey BenefitTypical Part
4140Good mix of strength + toughnessTransmission shafts, couplings
4340Higher toughness, deeper hardeningHeavy‑duty gears, axles
4130Easier to weld, slightly lower strengthRoll cages, frames

If you’re running precision CNC machining on these alloys, a strong process setup like in a dedicated CNC machine operations workflow helps you hold tight tolerances, especially on hardened 4140.

Reference Charts for Steel Tensile and Yield Strength

You should always have quick tensile and yield strength charts available for design checks and customer quotes.

Typical design‑level values (approximate, for quick comparison):

cURL Too many subrequests.Yield Strength (MPa)Tensile Strength (MPa)
1018 (cold drawn)~370–420~440–480
1045 (normalized)~380–415~570–625
4140 (QT, ~30–32 HRC)cURL Too many subrequests.cURL Too many subrequests.
cURL Too many subrequests.cURL Too many subrequests.cURL Too many subrequests.

cURL Too many subrequests. cURL Too many subrequests.; cURL Too many subrequests.

cURL Too many subrequests.

cURL Too many subrequests.

  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
  • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.
    • cURL Too many subrequests.

cURL Too many subrequests. downloadable PDFs so your team can check material selection, machining strategy, and heat‑treat decisions in seconds instead of hunting through specs.

For more advanced alloys or high‑temp environments (aerospace, energy), it also helps to cross‑reference our high‑temperature alloy insights so you know when standard steels like 1018/4140 are no longer enough: high‑temperature alloy insights and applications.

cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
ko_KRKorean
en_GBEnglish es_PESpanish (Peru) de_DEGerman es_ESSpanish (Spain) it_ITItalian ko_KRKorean
We'd love to hear from you

Stay Connected

Quick Contact

  • inquire@vast-cast.com
  • +86-546-8781583
  • +86 1334 506 4499

Send us a Message