Surface quality inspectionSurface quality inspection is mainly the inspection of materials, appearance, shape, and surface defects
19 Ovality: The phenomenon that the diameter of a metal material with a circular section is unequal in all directions on the same section. The ovality is expressed by the difference between the maximum and minimum diameters on the same cross-section, and the standards are different for different materials.
20 Bending, curvature: Bending is the rolled material. A general term for an uneven, curvilinear shape in length or width. If the degree of unevenness is expressed numerically, it is called curvature.
21 Twist ** bar rolled material along the longitudinal axis into a spiral.
22 Sickle bend (side bend): refers to the bending of a metal plate, with and a shape close to a rectangular section along the length (narrow side), with a concave curve on one side and a convex curve on the other side, which is called"Scythe bend"。Expressed in terms of recessed height.
23 Scoop curvature: refers to the undulating wave phenomenon that occurs at the same time in the length and width direction of the plate or belt, forming a scoop curvature, which is called scoop curvature. The numerical value that indicates the degree of curvature is called the curvature of the scoop.
24 Surface cracks: Cracks in the surface of metal objects.
25 Ears: The protrusions that extend along the rolling direction due to improper roll fitting and other reasons are called ears.
26 Bracketing: Refers to a straight or arc-shaped groove on the surface of the material, and the bottom of the groove can usually be seen.
27 Scarring: Refers to tongue-shaped, nail-like or fish-scale flakes that are unevenly distributed on the surface of a metal material.
28. Bonding: the mutual adhesion between the layers and the points, lines and surfaces between the layers of metal plates, foils and strips during the annealing of stacking. After being lifted, there are traces of bonding left on the surface, which is called bonding.
29 Iron oxide scale: Iron oxide scale refers to the metal oxide formed on the surface of the material during heating, rolling and cooling.
30 Folding: It is a surface defect formed by the metal in the hot rolling process (or forging), and the surface of the bimetallic layer is folded with each other, and it coincides in a straight line or curve.
31 Pockmarks: Refers to the uneven and rough surface of a metal material.
32 Subcutaneous bubbles: The surface of metal materials presents irregular distribution, different sizes, different shapes, small rounded bumps around them, and cracked bumps are chicken claw-shaped cracks or tongue-like scars, which are called bubbles. The causes of surface defects are mainly due to improper production, transportation, loading and unloading, storage and other operations. Depending on the impact on use, there are defects that do not allow exceeding the limit at all. Some defects, although not present, are not allowed to be exceeded;Whether various surface defects are allowed to exist, or the extent to which they are allowed, are clearly stipulated in the relevant standards.
Find out belowinconel 686 ：
Inconel 686 N06686 is a Ni-Cr-Mo solution-strengthened corrosion-resistant nickel-based alloy with excellent corrosion resistance in harsh corrosive environments, mainly used in heat exchangers, reaction vessels, conveyor pipes, etc. for chemical treatment, pollution control, papermaking, industrial and municipal waste treatment, etc.
According to the U.S. Huntington Special Materials Company, the Inconel 686 alloy with excellent corrosion resistance has replaced the K-500 alloy used by the U.S. sea ** ship as a connector. Alloy 686 is a solution-strengthened alloy that achieves high strength through cold working. In particular, cold-worked alloy 686 shows outstanding resistance to hydrogen embrittlement and corrosion, such as excellent strength, ductility and toughness. Manufactured from 38 inm (15 in) diameter cold-worked alloy 686 bars13×33cm(0.5 13 inches) bolts have a standard R1TR ultimate tensile strength of 993MPa, and these machined bolts show good performance in the middle of the machined connection and wedge tension test.
inconel686(uns n06686/w.nr. 2.4606)
Chemical composition (%)
Ni Yu. cr19.0-23.0
f≤2.0mo15.0-17.0
ti0.02-0.25
w3.0-4.4
c≤0.01
mn≤0.75
s≤0.02
si≤0.08
p≤0.04
Physical properties (room temperature):
Density (g cm3) 873
Melting point ( ) 1338-1380
Specific heat (j kg- ) 373
Resistivity (ohm circ mil ft) 7444
Uniform corrosion of Inconel products can occur in acidic or hot alkaline solutions. After this mechanism can estimate the loss, and in the planning promised. The corrosion rate of the inconel product is very slow, the metal is in a passive state, generally the corrosion resistance is better with a larger chromium content, but other solutes can be harmful.
The chemical composition of the inconel steel product near the grain boundaries is able to be modified by precipitationof chromium-rich particles. The resulting chromium-poor zone at the grain boundary makes the 4Cr13 stainless steel tubing product susceptible to intergranular anode attack, even in stress-free conditions.
Designating Inconel steel products means that the 12% CR content is more than a point. Most of the stainless steels are based on the Fe-Cr-C Fe-Cr-Ni-C system, but are also important for other alloying elements.
Inconel steel products are able to be present in several crystal ways, the most common of which are body-centered cubic (BCC) and face-centered cubic (FCC). In pure iron, the FCC structure still exists between 910 and 1400 below, this moment of distance below and above the body-centered cubic structure (up to 1539 below the melting temperature.
The importance of the metallurgical transformation of Inconel steel products at this stage cannot be overestimated. This conversion allows for a wide range of microstructures to achieve manipulated heat treatment. Essentially with microstructure, mechanical function, therefore, inconel steel products are able to obtain strength, toughness, etc. within a very large scale. Conventional production of Inconel steel 100 MPa exceeds 1 GPA and has a strong competitive strength. Therefore, the primary importance is the knowledge of the relative stability of the BCC and FCC structures of iron Inconel steels.
Characteristics: Excellent corrosion resistance, can be used as a universal weld filler metal.
Alloy 686 was specifically developed to be able to find an alloy that exhibits excellent corrosion resistance in many harsh corrosive environments.
Alloy 686 is used in the harshest working conditions, mainly for chemical treatment, pollution prevention, pulp and paper, industrial waste and domestic waste treatment. Chemical processing consists of heat exchangers, reactors, evaporators, and transmission pipelines. In terms of air pollution prevention and control, there are chimney fabrics, pipes, furnace doors, scrubbers, flue gas reheaters, propellers, and covers.
Product methods available
Pipes, sheets, plates, strips, round bars, hexagonal bars, wires, forgings
The main criteria that can be executed
uns n06686
astm b163, b462, b564, b574, b575, b619, b622, b626, b751, b775, b829, b906, f467, f467m, f468, f468m
asme sb-163, sb-462, sb-564, sb-574, sb-575, sb-619, sb-622, sb-626, sb-751, sb-775, sb-829, sb-906
asme code case 2198
sae/ams j2295, j2271, j2655, j2280, j2485
din 17744, 17750, 17751, 17752, 17753, 17754
werkstoff nr.2.4606
vdtüv 515
nace mr-0175/iso 15156