...just wondering. I know stainless is harder then carbon steel ....just try and cut stainless with a hack saw....

What is in stainless alloy anyway?

There are different stainless alloys with different properties used for a myriad of products, and not all are harder than all carbon steel. You may be comparing the cheapest mild hot rolled steel with a harder stainless alloy.
In the US, you can call it "stainless" if the alloy has at least 10.5% chromium. Nickel, carbon, molybdenum, manganese, copper, and even aluminum and titanium can be in stainless alloys.

__________________
Science plus Art

Member Dave T posted a very interesting thread about gun metalurgy a while back,
Here is a link if interested

An Engineer's take on S&W.

It's a pretty broad statement, given the different alloys used in guns, & the different measurements of "strength", such as tensile, shear, compression, etc., but, it's generally accepted that the carbon alloys used in gun manufacturing are actually slightly stronger than the stainless alloys. FWIW.

I'm a hobby knifemaker. I mostly use carbon (1095) for my blades. I use some stainless, but I prefer the character and ease of sharpening that carbon gives you for the price point. If you are comparing basic old carbon to basic stainless, then the carbon will probably be tougher depending on the heat treatment. When I say tougher, I mean won't break and will roll an edge opposed to chipping. Heat treatment really has an amazing amout to do with steel toughness and what you want. A keen edge that will last a long time but can be brittle and chip, or something that is easy to sharpen and won't break if torqued.
Then there are "super steels". But we don't need to get into that.

There are hundreds of types of stainless with a wide array of compounds that make each their own. There is also annealed steel and heat treated. Annealed is soft and easy to work with. Heat treating makes it stronger.

Here is a great site all about steel:
Interactive Knife Steel Composition Chart Version 4.51

The most common grade of stainless steel used in firearms is 416R. Not the only one, but common. You can look up the analysis and physical properties and compare them to chrome moly ("blue") steel of say 4140 grade.

No it's not.tends to gall when machining because of its soft nature.Also galling only present in stainless steel slides on automatics.

What the OP is observing when cutting stainless steel is a phenomenon known as "work hardening". In general, the 300-series (austenetic) stainless steels are more difficult to machine due to the higher chromium and nickel content and the formation of the austenetic structure at solidification. The iron-nickel-chromium alloy forms a structire wherein the iron and nickel have alloyed, and the chromium tends to be depleted in the inner region of the grain, while of much higher concentration at and along the grain boundary, where it forms a complex with the carbon in the steel. The lack of alloying with the carbon, and its preferential deposition along the grain boundaries is why the 300 series stainlesses do not respond to hardening by heat treating. They remain ductle, and high in fracture toughness, which is why they are more difficult to machine than ordinary carbon steels, which have a lower fracture toughness.

Are stainless steels "Stronger"? In general, the answer is no, because the tensile strength of stainless is generally lower than that of heat treated carbon and alloy steels. Since carbon and low alloy steels are normally heat treated to enhance their characteristic physical properties (hardness, tensile strength) and most common stainless steels are non-responsive to heat tretment, it is safe to say, as a general rule, carbon steel is "stronger" than stainless.

There are, of course exceptions. The 400-series stainless steels (ferritic) can be heat treated to alter their native properties, and enhance desired properties. The precipitation hardening stainlesses (17-4PH as an example) can be hardened by heat treating, and then age-hardened further.

The complexity in what properties a steel has, how they may be altered by variou heat treatments, what effect the atmosphere while being heat treated has on the properties, and what post-heat treatment regimen the material is subjected to means that a metallurgical engineer has good job security, and the choice of the proper material is vital to the ultimate function of the item manufactured.

There are a great many different alloys of both carbon steels and stainless steels. And heat treating will make major changes in hardness and tensile strength. There is no answer to your question without specifying the exact alloys and heat treatments.

It all depends upon the exact makeup of the metal as others have said, but Warren Paige wrote years ago in one of his books that stainless barrels were generally softer than blue barrels, but the stainless was more heat resistant.

I do know that when I was up at the factory in the early 70's I was told that the stainless alloys used in guns expanded and contracted at a different rate than the 4140 chrome moly ( carbon )steel, thus the issues they had with the fit of the gas seals, cylinder, crane leg ,etc...and we noted the stainless was rougher,on cutting tools, as noted above, tended to gall, especially when parts rubbed against each other, like a slide on the frame, but the surface of stainless is much softer, and marks easier than the carbon steel, cleans fairly easy with a 3M scothbrite pad...........I recall a conversation with Mr Wesson ( Dan) that he for one did not care for the stainless alloy used in gun making, lots of problems in the first makings of the stainless guns in the 1960's.............

__________________
dan
NRA Benefactor,PMA

Let's not forget that weight saving concept of "Aluminum Armor Plate" when considering alloy frames and stainless steel slides.

On stainless steel semi-autos, the frame and slide are made of different alloys to prevent galling on the frame/slide rails. Just remember steel is real, and stainless is real steel.

__________________
S&WHF 366

Gun barrels must be tough and only somewhat hard. On that basis, 400 series stainless steel and low alloy carbon steel (e.g., 4140) are suitable. Knife blades are more demanding in both hardness and toughness.

The "best" stainless steel for knife blades is represented by S30V and VG-10. These steels are compounded in powder form, so the composition and crystal structure can be tightly controlled. This powder is then sintered into blocks which are then ground into knife blades, possibly with pre-forming to reduce the selvage. These example have more carbon than will dissolve in carbon steel, which tops out in 1095 used for truck springs and such. 1095 is predictable, hardenable to 55-60 RC, and relatively easily sharpened. However the edge tends to be brittle and easily dulled by micro breaks.

Machining stainless steel is difficult because of work hardening, especially in the high chromium alloys. It is also somewhat "gummy" and builds up on the tool, causing drag and galling on the work piece.