Everything You Need to Know About Hardness of Materials

Do you worry about parts that break too soon? Are your machines failing because materials can’t stand up to wear? Does your product quality suffer from using the wrong materials?

At Istar Machining, we see these problems every day. The wrong material hardness can cost you time, money, and your good name.

Let’s fix that! This guide will help you pick the right materials and work with a top CNC machining service like Istar Machining to get parts that last.

Why Does Material Hardness Matter?

Hardness is how well a material fights back against dents, cuts, or scratches. Think of it like this:

• Soft materials – easy to cut, dent, or scratch
• Hard materials – tough to change their shape

This matters a lot for:

• Cars
• Planes
• Tools
• Machine parts

The wrong hardness means parts wear out fast. But too hard can make parts snap! At Istar Machining, we help you find the just right hardness for your parts.

How We Test Material Hardness

There are many ways to check how hard a material is. Each test works best for some materials.

Indentation Tests

These tests push into the material to see how it responds:

Brinell Test

• Uses a hard ball
• Pushes with 500-3000 kg force
• Best for: soft metals like aluminum
• Leaves a big mark

Vickers Test

• Uses a diamond point
• Very light touch (1-1000 gf)
• Best for: thin parts or coatings
• Most exact but takes longer

Rockwell Test

• Checks how deep the test point goes
• Uses 60-150 kg force
• Best for: most factory metals
• Fast and less harmful to parts

The Mohs Scale

This is a simple 1-10 scale:

• 1 = Talc (very soft)
• 10 = Diamond (super hard)

It’s great for rocks and minerals but not so good for metals. At Istar Machining, we use more exact tests for your custom CNC machining needs.

Shore Test

For soft stuff like rubber and plastic, we use the Shore test. It works by seeing how much a part bounces back when pushed.

What Affects Material Hardness?

Many things change how hard a material is. As a precision CNC machining expert, Istar Machining understands these factors well:

What’s In The Material

The tiny parts inside materials change how hard they are:

• Crystal shape (why diamond is so hard)
• What metals are mixed in (more carbon = harder steel)
• How tight the atoms pack together

How It Was Made

The way we treat materials changes their hardness:

• Heat treatment – heating and cooling to make metals harder
• Work hardening – bending or hitting to make stronger
• Surface treatments – making just the outside hard

This is why at Istar Machining, we not only cut the right shapes, but we make sure the material matches your needs.

Outside Factors

Even after making a part, these things can change its hardness:

• Heat – hot parts get softer
• Rust – makes parts weaker
• Stress – parts hit over and over can get harder or softer

Real-World Hardness Applications

Here’s how different jobs need different hardness levels:

Cars

In cars, we need:

• Hard gears (Rockwell C 50-55) to last long
• Tough frames that won’t crack (Brinell 120-180)

Our automotive CNC machining team knows how to match the right hardness to each part.

Planes

For planes, we need:

• Light but strong parts (Titanium: Vickers 340)
• Parts that won’t break in the air

Istar Machining has special skills in aerospace CNC machining to meet these needs.

Medical Tools

Medical parts need:

• Just right hardness (Rockwell C 28-35)
• Must not break inside people
• Must not rust

For medical CNC machining, we follow strict rules to make safe parts.

Building Tools

For drill bits and cutting tools:

• Super hard coatings (Vickers 1500-2000)
• Made to cut through rocks and metals

Material Hardness Comparison Table

Here’s how common materials compare:

At Istar Machining, we can work with all these materials in our CNC milling and CNC turning processes.

Common Problems and Fixes

When making parts, these hardness problems come up:

Bad Surface Prep

Problem: Tests are wrong by 10-15% if surfaces aren’t smooth. Fix: We clean and polish all test spots first.

Hard vs. Tough Trade-Off

Problem: Very hard parts (like glass) break too easy. Fix: We make parts with hard outside and tough inside.

Wrong Test Choice

Problem: Using Mohs scale for metals gives bad info. Fix: We pick the right test for each material.

Rust Makes Parts Weak

Problem: Parts in wet places lose 20% hardness in 5 years. Fix: We add special coatings to stop rust.

Key Facts About Hardness

Did you know:

• The market for hardness testing is growing 5.2% each year.
• Most factory parts (65%) need heat treatment for the right hardness.
• Wrong hardness testing costs up to $18,000 per year in wasted parts.

Questions People Ask

Choosing The Right Hardness Test

Not sure which test to use? Here’s a simple guide:

• For big metal parts: Use Brinell test
• For small, exact areas: Use Vickers test
• For quick factory checks: Use Rockwell test
• For soft plastics and rubber: Use Shore test

How Istar Machining Uses Hardness Knowledge

At Istar Machining, we use our deep understanding of material hardness to:

1. Pick the right material for your CNC prototype machining
2. Test all materials to make sure they match what you need
3. Use the best cutting tools for each material hardness
4. Suggest better materials if we see a better option
5. Treat parts after machining to get the perfect hardness

The Problem With Most Machine Shops

Most shops just cut what you ask for. They don’t think about:

• If the material is too soft for your use
• If a harder material would last longer
• If heat from machining will change the hardness

This means you get parts that fail too soon or cost too much or don’t work right.

The Istar Machining Solution

We do it better:

1. We ask about your part’s job, not just its size
2. We test materials before and after machining
3. We keep records of what works best
4. We can heat treat parts to get the right hardness
5. We know which materials work best for each job

What To Do Next

If material hardness matters for your parts:

1. Talk to us about what your parts need to do
2. Ask about our material testing options
3. Let us show you samples of different hardness levels
4. Compare prices of different materials
5. Start with a small test of different options

Conclusion: Making Hardness Work For You

Material hardness isn’t just a number – it’s the key to parts that work right and last long.

The wrong hardness means:

• Parts that wear out too fast
• Machines that break down
• Products that fail in use

The right hardness means:

• Parts that last longer
• Machines that keep running
• Products that customers love

At Istar Machining, we’ll help you get it right. Talk to us about your next project today!