WCB Tensile Failure
WCB Tensile Failure
(OP)
WCB with Normalized (940 Deg C) & Tempered (640 Deg C) are getting failure with lower yield and lower UTS. Please guide me to resolve it.
Similarly in the case of Inconel 825 (CU5MCuC) getting failure in elongation (Solution annealed 1900 Deg C & Stabilized @ 960 Deg C). How to solve it, the fracture surface looks like brittle fracture no appearance of cup & Cone.
And is it required to add Ti & Al in the case of Carbon Steel (WCB, LCB) & Low alloy steels (WC6, WC9 & C5). Because am not getting toughness value @-10 deg C. If I stopper am getting good values in +20, +10, 0 Deg but in -10 Deg am not getting more than 27 Joules.
Please help me.
Similarly in the case of Inconel 825 (CU5MCuC) getting failure in elongation (Solution annealed 1900 Deg C & Stabilized @ 960 Deg C). How to solve it, the fracture surface looks like brittle fracture no appearance of cup & Cone.
And is it required to add Ti & Al in the case of Carbon Steel (WCB, LCB) & Low alloy steels (WC6, WC9 & C5). Because am not getting toughness value @-10 deg C. If I stopper am getting good values in +20, +10, 0 Deg but in -10 Deg am not getting more than 27 Joules.
Please help me.





RE: WCB Tensile Failure
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
RE: WCB Tensile Failure
What is your residual Al in LCB, WC6 etc. There is no requirement to add Ti for thee grades. What is the heat treatment cycle for LCB grade?
In order to get specific advice and responses, do not cloud too many issues in one post. Discuss each issue separately, it will help, else you may be considered in poor light.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
My residual Al is 0.06 - 0.08%, For LCB we are doing quench & tempering but sometimes we are adding Nickel to achieve impact value but impact is getting fail. What I have to do?
And please suggest me in the case of Inconel 825 (CU5MCuC), elongation failure after solution annealing & stabilizing.
Next time I will post the issues separately.
RE: WCB Tensile Failure
Inconel 825 - http://www.sandmeyersteel.com/A825.html
"Alloy 825 has good mechanical properties from cryogenic to moderately high temperatures. Exposure to temperatures above 1000°F (540°C) can result in changes to the microstructure that will significantly lower ductility and impact strength. For that reason, Alloy 825 should not be utilized at temperatures where creep-rupture properties are design factors."
There is no reason to perform a stabilization heat treatment for this alloy.
RE: WCB Tensile Failure
While not germane to grade WCB, I have recently looked at MTRs for SA-106B where Mn was < 0.44%. While the ambient temp properties meet the requirements, don't expect the same for the higher temp. properties. And as for impact toughness properties - forget about it!!!
RE: WCB Tensile Failure
Perform a search in this forum for "LCB grade castings", you will see several good discussions.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
I can't help out with the 825 alloy.
RE: WCB Tensile Failure
AODs in steel foundries has not been popular. The smallest AOD to my mind ( subject to correction) is about 5 tons capacity. Most steel foundries operate in batch of 1 ton .
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
I know that, however I also know of foundries who send their revert out for AOD processing and a local foundry has a small vessel so it isn't unprecedented. It all depends on how critical the work is.
RE: WCB Tensile Failure
WCB,LCB, WC 6/9 grades are very common and straight forward for any valve casting manufacturer. If a foundry fails to achieve the metallurgy for these alloys , my advice would be, either upgrade or move away.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
RE: WCB Tensile Failure
@metengr,
But as per ASTM A494, for CU5MCuC "Heat to 2100°F [1150°C] minimum, hold for sufficient time to heat castings to temperature, quench in water. Stabilize at 1725-1815°F [940-990°C], hold for sufficient time to heat castings to temperature, quench in water or rapid cool by other means".
So how can I skip the stabilization process.
@arunmrao & @jwhit,
I have attached the chem & mechnical of 2 heats. For me few heats only getting failed and most of the heats are getting clear with out any AOD, VOD process. Please see the spec and what tramp elements I can control to achieve the mechanical in WCB.
Please suggest me.
RE: WCB Tensile Failure
Element Pass Heat Chemical Fail Heat Chemical
C 0.21% 0.20%
Mn 0.87% 0.93%
Si 0.46% 0.35%
P 0.017% 0.019%
S 0.013% 0.011%
Cu 0.09% 0.010%
Ni 0.03% 0.020%
Cr 0.10% 0.15%
Mo 0.012% 0.008%
V 0.005% 0.011%
Nb 0.004% 0.005%
N 0.014% 0.013%
W 0.007% 0.007%
Al 0.039% 0.044%
Ti 0.001% 0.002%
Zr 0.004% 0.005%
Sn 0.004% 0.004%
Fe 98.01% 98.09%
CEq 0.386% 0.391%
Res 0.237% 0.199%
Se 0.002% 0.002%
Pb 0.001% 0.001%
B 0.001% 0.001%
Sb 0.001% 0.001%
Zn 0.001% 0.002%
As 0.006% 0.005%
Bi 0.002% 0.008%
Ta 0.018% 0.027%
Ca 0.001% 0.001%
Ce 0.040% 0.039%
La 0.022% 0.027%
Co 0.003% 0.003%
Y.Sgth 295.79 MPa 269.29 MPa
UTS 504.42 MPa 459.82 MPa
%E 36.28% 40.32%
%R 57.28% 66.82%
RE: WCB Tensile Failure
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
What type - attached to castings, separately cast.
Were they heat treated on the same place in furnace? With castings or separated?
What is the grain size?
Any visible defect(microporosity, hole,...) on fracture of the tensile test specimen?
The chemistry is from the test block or heat sample?
RE: WCB Tensile Failure
Some of my customer asking 0.25% Max. Depends upon the casting thickness we are giving soaking time.
@Dalinus
Its normal keel block - 230mm length and 25 mm thickness.
separately cast
with casting
Grain size will be 7
Hmm, no visible defects.
chemistry from heat sample. (sometimes chemical is getting varied between test block and heat sample.
RE: WCB Tensile Failure
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
Are you decarburizing the test material extensively with a 6 hr. hold? Are you getting a cup and cone tensile fracture? Any possible issues with location of the test material in the furnace? If anything else comes to mind, I will add it.
RE: WCB Tensile Failure
RE: WCB Tensile Failure
RE: WCB Tensile Failure
Yes, the cast version of this alloy is similar to a wrought version of Alloy 825. It would appear that for castings, a two step heat treatment is required; homogenization treatment/quench followed by a lower temperature solution anneal(stabilization) and quench.
I think you need to perform a more detailed metallurgical analysis of the fracture surface using an SEM and perform metallographic examination to better understand why this heat of material has reduced ductility. If the fracture surface as viewed under the SEM is intergranular, this could be related to segregation of elements that result in grain boundary weakening. More lab work is needed in lieu of speculation or list of possible causes.
RE: WCB Tensile Failure
It looks like the failed sample was tempered on higher temperature than it was needed.
Increasing carbon content would probably lower impact test values, increasing Mn content would be better. Dont know your CE limitations. If there is none, is it possible to go up to 1.28 according to note B in Table 1?
Double normalizing could also help with your impact test values (not my original idea, somebody from this forum gave me this advise months ago).
Dalin
RE: WCB Tensile Failure
RE: WCB Tensile Failure
Good point, you brought some sanity into the discussion. Hope, the OP will respond .
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WCB Tensile Failure
RE: WCB Tensile Failure
RE: WCB Tensile Failure
RE: WCB Tensile Failure
Good luck.