What is the difference between Quality and Quality Grade?

Quality: its definition is very broad, and it concerns with the totality of features and characteristics of a product or service that bear on its ability to satisfy a given need.
This provides a fitness for purpose sense relating to the ability of goods or services to satisfy a given need.
While Manufacturing quality is conformance of the product to engineering’s drawings and specifications.
This provides a quantitative sense for evaluations known as quality levels of conformance.
Quality and grade are not the same words: - Grade involves a process for ranking or sorting of products and features for a comparative sense for the degree of excellence.
- One well known merchandiser provides good examples of product grades listed for sale as: good, better, best.
We can distinguish between aspects of quality and grade: - So Grade is: A rank indication of the degree of refinement, features, or capabilities for materials and products.
- When grade is applied to a service, it represents the diversity of functions or facilities provided.
High grade products have low quality if they do not meet specifications.
Low-grade products have high quality if they meet or exceed the specifications.
Example1: in beef manufacturing: == A quality grade is a composite evaluation of factors that affect palatability of meat (tenderness, juiciness, and flavor).
== These factors include carcass maturity, firmness, texture, and color of lean, and the amount and distribution of marbling within the lean.
== Beef carcass quality grading is based on (1) degree of marbling and (2) degree of maturity - Example 2: == If you buy a cheap, simple (basic model) low grade cell phone for your normal usage.
It doesn't have any advanced features, but it works.
It never gives you any trouble, always works flawlessly and it is defect free — No problem at all.
== In other words, you can say that the quality of this cell phone is very high.
Although, it is a low grade product, it keeps you happy and satisfied == A low grade is never a problem because when you buy a service or product, because you know that you are paying for a low-grade product or service and expect the performance as per its category.
== You never buy a low grade product and expect it to perform like a high grade.
However, a low quality is always a problem because it does not fulfill your expectation.
== So, it is better to know that: + low quality does not low grade.
+ low quality is not acceptable + low grade is never a problem and it is acceptable + a product or service, regardless of its grade must be of high quality.

Grade talks about the Characteristics and features of a product .
while Quality talks about the degree that the inherent characteristics of a product fulfill its requirements.
Thus, a high Grade product can have a low quality and vice versa.
Quality talks about the durability of a product while Grade talks about the fancifulness of the product.

Grade talks about the Characteristics and features of a product while Quality talks about the degree that the inherent characteristics of a product fulfill its requirements.
Thus, a high Grade product can have a low quality and vice versa.

Quality means meeting the specific requirements.

Quality Grade means meeting an option.

Example:

A manufactured car meets the quality requirements however the quality grade is less i.e. a base model.

ok, I'll explain it in simple words: Quality is measure of variation while grade is reference to specification.
Imagine you are selling a car: which is better Mercedes or KIA? the first answer is usually Mercedes, but let’s consider this as an average citizen who cares about Car Fuel Consumption above all others.
KIA win the deal quality is related to your targeted customer.
now Grade A product is designed to be sold for a specific target group and grade B is designed to be sold for another target.
Grade is usually reflected in price you can't compare apples and oranges.
But if you want to compare2 cars at the same categories, like Mercedes and BMW.
Then meeting specification within lower cost is better quality the measure of quality is variation between the same product: the number of defects, warranity claims and cost of quality …etc

Quality is: “The degree to which a set of inherent characteristics fulfills requirements”. Grade is: “A category or rank used to distinguish items that have the same functional use ( example: “hammer”), but do not share the same requirements for quality ( different hammers may need to withstand different amounts of force)”. A Low Quality product or service is always a problem. But a Low Grade product may only mean that it does not have enough of the required features - it may be a scaled down version of an item. If you take a diamond analogy, a high quality diamond may be based on the colour, or weight. If2 high quality diamonds are found at the same place, one may be low grade and one high grade - depending on the number of impurities present inside each one. Both have the same "Quality" because both are diamonds, both display the same colour, clarity and weight ( as a customer might expect )...but the number of impurities in one stone makes it a low grade. The high "Grade" stone has "Quality" that makes it more desireable.

Quality talks about the durability of a product while Grade talks about the fancifulness of the product

Quality is generalized concept used for the product, service, technical aid whereas quality grade is quantification / evaluation of the quality in certain parameter.

SIMPLE : i would like to explain only in one sentence and that is that "the quality in any product /material which we like and appreciate to any one beside of us and the quality grade is called by my sight is excellent trade of mark of manufactured product by the company's worker and their labour experience and their qualities in their field".".

The basic quality is fitness of a product or service for which it was produced while grade is a attribute of the product other than the basic feature of the product like color,  design, application , material etc. Grade is also segregation of product in classes like plastic, metallic,  gold.

Quality is the minimum specification acceptable to the owner while the quality grade is the ranking of product according to its composition.