# Annealing 1045 Questions.   Would You Bother? Or Just Mill It?



## countryguy (Apr 11, 2015)

Morning Everyone!  Still digging into the new Mill on A36 which cuts like a dream on this 30taper.   So now the basics are done, the Axes in 1045 flame cut (plasma) are next.   We'll grind down the edges and scale beforehand.    The 1045 is pretty tough.  The Carbides are expensive and we're wondering if we should consider Annealing first?    I know I've covered the 1045 Milling Q's in past posts early on last fall. Put we have a old furnace someone gave us.  It needs an element and a controller.   We're wondering if you think it's worth annealing before Milling then re-harden after?   

ALLOY INFORMATION FOR AISI 1045 CARBON STEEL

CHEMICAL ANALYSIS
C    Carbon 0.43 – 0.50
Mn    Manganese 0.60 – 0.90 max
P    Phosphorus 0.04 max
S    Sulfur 0.50 max
GENERAL CHARACTERISTICS
C1045 is a medium carbon, medium tensile steel supplied as forged or normalized. This steel shows good strength, toughness and wear resistance. C1045 will through harden to 2.5” (63mm) with a tensile strength of 66 – 120 Ksi (620 – 850 MPa).

C1045 is a versatile medium carbon engineering steel that can be through hardened to about 2.5” (63mm), as well as being flame or induction hardened to Rc58. The steel can be readily welded and machined providing correct procedures are followed.

APPLICATIONS OF AISI 1045
This grade of steel is used for axles, bolts, forged connecting rods, crankshafts, torsion bars, light gears, guide rods etc.

FORGING AISI 1045 CARBON STEEL
C1045 is forged from 2100 – 2300 º F (1150 – 1280 º C) down to a temperature in the range1600 – 1700 º F (870 – 925 º C.). The actual forging and finishing temperatures will depend on a number of factors, including overall reduction during forging and complexity of part being forged. Experience alone will determine near exact values for these two parameters. Parts are air cooled after forging.

HEAT TREATMENT
Heat treatment is carried out on this grade to render it suitable for machining and to impart to it specified mechanical properties.

ANNEALING
Full annealing of small C1045 forgings is carried out between 1450 and 1600 º F (790 – 870 º C) followed by furnace cooling at 50 º F (10 º C) per hour, to 1200 º F (650 º C) and air cooling.

NORMALIZING
The normalizing temperature range for this grade is typically 1550 – 1600 º F (840 – 870 º C,) Normalizing is followed by cooling in still air. When forgings are normalized before hardening and tempering or other heat treatment, the upper range of the normalizing temperature is used. When normalizing is the final treatment, the lower temperature range is used.

HARDENING
Hardening of this grade is carried out from an austenitizing temperature of 1510 – 1580 º F (820 – 860 º C) and oil or water quenching.

Flame and induction hardening may be carried out by heating quickly to the desired case depth and quenching in water or oil. This should be followed by a tempering treatment at 300 – 400 º F (150 – 200 º C) to reduce stresses in the case without affecting its hardness. A surface hardness of Rc 58 may be obtained by this treatment.

TEMPERING
Tempering after normal hardening and oil or water quenching is carried out at 750 – 1260 º F (400 – 680 º C) to give the required mechanical properties as determined by practical experience.

MACHINABILITY
Machinability of C1045 is good providing the full annealing cycle described above is used, ensuring a coarse lamellar pearlite to coarse spheroidite microstructure.


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## JimDawson (Apr 11, 2015)

I guess I would try one and see how it machines.  Then make a determination as to whether it needs to be annealed.  I assume the material you are buying is furnished in the annealed state, so the real problem is only near the plasma cut edge.  Cobalt end mills might be a good choice for this application.


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## countryguy (Apr 11, 2015)

Thanks Jim.  I will call ALRO on Monday.  I cannot find any info on the site about the plate and if sold as 'Annealed' from the  hot rolled?   It's a good question.    Was also considering indexable & inserts possibly?  There are some decent prices I'm seeing.  

http://www.alro.com/divsteel/metals_gridpt.aspx?gp=0031&gpn=1045&Mat=CARBON STEEL&Type=Plate


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## countryguy (Apr 11, 2015)

From what I can tell,  It is to be annealed post part cutting?   anyway-  Thanks for all the help to us Beginners gang!   
CG 

1045 hot roll plate is a silicon killed medium carbon steel. In the as-rolled condition, higher carbon content imparts increased strength over low carbon steels, such as 1018. 1045 hot roll plate is often stress relieved, normalized, or annealed after burning shapes to size to allow for easier machining. Response to heat treatment is excellent and the resultant mechanical properties which can be obtained permit wide usage in the production of machinery parts and shafts. Parts made from 1045 hot roll plate can be hammer forged, heat treated for further durability, or used in the non-heat-treated condition. Machinability is good, but forming and welding qualities are limited.


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## T Bredehoft (Apr 11, 2015)

I'd hit it with a file, if the file skates, anneal it, if the file digs in and cuts it, go ahead and machine it.


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## countryguy (Apr 11, 2015)

Ohhh  it skates and bounces...   I did this same thing w/ the hobby mill and ruined some expensive carbides.  My stepover then was .003-007 and depths were .003 .004....  I mean just terrible #'s and it just tore up the corners of the end mills.     Once you get down into the  middle it does seem somewhat softer but this stuff is just wicked.  ;-)   How can anyone mill or work w/ 1060 and 1090 Wow!  Respect for hard miller's out there.  ;- )


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## randyc (Apr 11, 2015)

This isn't a recommendation about solving your problem but just a heads-up regarding the expense of carbide end mills.  Solid carbide end mills on eBay are getting cheaper all the time.  I've purchase three lots in the past year, sizes from 1/8 to 1/2, both 3-flute and 4-flute.  Average cost has been about $3 each.


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## T Bredehoft (Apr 11, 2015)

Last week I bought some 4140, 3/4" sheet, flame cut to 3/4 wide, 12 inches long, "as rolled." I hit it with a hack saw and skidded all over the piece. Harder than the proverbial hinges....

Today I set up the grill we bought when the power was out for a week, so we could cook, filled the tray with charcoal, put my two bars in it and lit the charcoal. When it got cool enough to lift, after probably 10 or 12 hours, I brought them into the shop, put one in the vise and attacked it with the hack saw. It cuts like annealed 4140, not easy, but it will cut. 

Doesn't smell like bar-be-cue, either.


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